I've played this game a lot for a long time and I have a lot of feelings on this. I'm about to write an essay just to get it all out in one post; an essay that you can read or not, but please don't respond to it if you aren't going to read it.
Right now people without a *ton* of disposable income do not get to experience the whole game of magic. They get to experience far less of the game than those who can spend thousands of dollars per deck. This goes for plenty of cards that are newer and just not printed anyway close to demand like enemy color fetches, but it goes for many more cards than that. The RL is honestly the worst offender here, because it changes the calculus from 'you just need to invest a bit in your hobby for a while and then you can play with these cards too' into 'you will never be able to play these cards unless you have large sums of disposable income or spend many years managing to trade up into even a few of them'. It's changed the dynamic between players of means and those with little to no means from a difference in the rate of acquisition of full access to the game to a binary state of who does and doesn't get to have access at all. It's the difference between Tundras being $20-40, or even $80 and being $300-600. The first situation is still hypothetically obtainable for someone on a limited budget to eventually obtain, the latter is strictly not possible on any rational time scale for anyone with a small budget for their hobbies and more pressing necessary bills to pay.
I've been playing for a long time; since I was about 11, so coming up on 22 years. It was easier to be a franchised player as a teen working a part-time garbage minimum wage job then than it is now as a full time working professional with a STEM graduate degree working in my field, which already makes me far luckier than most when it comes to finances. The only way I would be able to have the sort of collection I had back then was if I hadn't gotten almost my entire collection stolen, because it was maybe $1000 dollars at the time it was stolen and today I could easily get $1k for a single playset of one of the blue OG duals and I'd be given that buyer a really good deal. That $1000 stolen from me then would cost me 10 times that or more to buy today and that's %$#% criminal. It's leading to am *extreme* level of socio-economic stratification of our %$#% hobby, one of the greatest games out there that you should *want* other people to play and to be feasibly accessible through a rational level of financial investment. You shouldn't want your game to turn into yet another gated community where only those with significant wealth or legacy connections get to have full access. The lines between what the haves and have nots get access to in Magic are far clearer in the past 5 years than they have been in the game's life and honestly, a zero-tolerance for proxies from anyone on the haves side of game access is classist as *%$#%* and comes across as someone who feels they should be entitled to the higher win rate they have *purchased*.
I've been on both sides of the enfranchisement fence so believe me when I say I can see and feel the difference in its height from then to now. It's the reason I went from a 'you should proxy stuff while you test it and then try to own all the cards you play in all the decks you play them as soon as possible after you know it's staying in the deck' alllllllll the way to the other side of 'just %$#% proxy whatever you want and *especially* proxy anything on the RL, I want to play against you and your ideas, not your wallet'.
Like, look, if your entire group doesn't have the kind of money to access the larger game and just one person is trying to force you to let them proxy a significant number of cards in all their decks when the rest of you aren't...then yeah it's a bit of a dick move that's often going to result in most of their decks suddenly being above the group. If the group wants to *all* play with limited access to the game then you have at least agreed on a power level, kinda. There are going to be strategies and synergies that just aren't as affected by cost gating and it's always going to be a feel-bad moment when you go to brainstorm on a deck and then find out that super cool interaction unique to the deck you're building isn't possible because some random, maybe not even a universally good card, is financially unobtainable because it's a RL card and so some speculator jacked the price up.
But...but, if your group has an uneven distribution of wealth and/or player game age that seriously skews collection size and access to the game then enforcing strict proxy bans or even 'as long as you own just one' is, again, classist as *%$#%* and is going to entitle those with significant free sums of money or a long unbroken chain of collection building to get to experience more of the game and likely to entitle them to high power and more wins. If you wanted more equal game access and more equal table power you'd be open to proxies and bring the hammer down on people abusing that generosity instead of locking people out of the same experience of the game you get to have.
Now, several people have talked about the problem of power-creep or people bringing inappropriate power levels of decks to tables as soon as they are allowed to proxy. Honestly, the counter-argument has been given already in the thread so I will just agree: if people do that when you allow them to proxy, it's the player that is the problem, not proxying as a tool; proxies as an amoral device, they do not make people do things they don't already want to do. That player is just telling you who they are and what they wanted to do all along, what they would do if they had unlimited funds for magic cards... and all you are doing by saying it's the proxies that are bad in that situation is that it's ok for players to do toxic %$#%$#% and be giant pub stomping assholes so long as they *pay for the right to do it*.
When you consider whether or not you disliked a card that was played against you, who printed the cardboard shouldn't be part of your emotional response. Your entire emotional response should be based on how you feel about the effects the card being played has on the game and whether or not you feel that card is too good or just doesn't belong in your group and your power level you want to play at. If someone plays a Gaea's Cradle and destroys your table through the sheer power that card brings to the strategy of their deck and you shouldn't think it's not ok to play at your table if it's a proxy but perfectly ok to play it if they spent hundreds of dollars for the right to. Imagine of the entire banned list of EDH had a clause that said *but you can ignore this if you pay $1000 for each card you want to play on this list*, would that suddenly make those cards more or less fun or more or less brokenly good? No, it would just entitle those with significant money for hobbies to significant advantages over you and others. The situation with proxies is basically no different. What the card does and how the player is using it in their deck should be the sole determining factors for how you feel about that card being played against you; if you are suddenly ok with players buying their wins over you and playing toxic decks because they paid for the right to do so then honestly you have some seriously internalized classist worldview tenants woven into your morality and emotional and logical headspace.
On the flip side of that if you are suddenly mad about someone playing a proxy of a RL card that isn't even all that broken and doesn't overpower the table/game, but just expensive as %$#% because of RL shenanigans (like, idk Drop of Honey)... then its the same deal. If someone proxied some ABUR duals to smooth out the mana base on their 5 color Ladies Looking Left or Chair Tribal deck so they could play their deck at the exact same speed as with basics, but just more smoothly and consistently play their games out each game they played and you lose you get angry or annoyed or upset than honestly, you are the problem in that equation. You are getting upset about something that *does not matter* and does not harm you or anyone else, even collectors. You're going to have to not immediately flip out and humor me as I walk through this analogy, but If that is you, you make about as much sense as someone arguing that their straight marriage is intrinsically harmed by the existence of gay marriage and that it is somehow more pure or valuable so long as their way of marriage is the only legitimate one. I mean, to be fair the arguments exist on entirely different planets in terms of the moral/immoral implications and the rights/privileges are stake, don't get me wrong; but the strain of logic used to support both is the same, an argument that the existence of something that does not implicitly cause harm to something of value you currently have will somehow magically cause harm or loss of value to you and others even though it clearly won't.
Now I'm going to end this Russian Epic by clarifying that Proxies aren't Counterfeits and that Counterfeits that are being created and passed off as real cards *are*, in fact, very harmful to just about everyone involved in magic from players to collectors to vendors. People who create counterfeits for the purpose of selling them to others are *thieves* and %$#% garbage human beings. If you make proxies they should be in some way obvious as proxies, of which is easily achievable; you should not be trying to fool anyone with you proxies, ever.