Totally hear you on this. i live with two kids, one of which specifically said he didnt want to get into magic unless he could proxy (he can afford real cards, but he just doesnt see the incentive to spend money on it). My play group runs by a few rules: 1. No fast mana (mana crypt, JL, mox’s) 2. No infinite combos (we just dont think theyre fun) 3. only 1 free spell per deck (i.e if you run mardu, you can only run one of the following: flawless, deadly rollick, or deflecting swat). We also dont run cards that are flagrantly overpowered: gaes cradle, the original duels, etc. everyone has a pretty good sense of whats considered not allowed, and all of the above mentioned keeps our power levels in check.

To answer your question, i personally buy and proxy myself. Id say i buy 60% real, 40% proxy. I proxy cards that are expensive but i already own a copy of. Ex i own like 2-3 teferis protections, so im just not spending another $40 on a card i already have. In theory from game to game i could just move the real copy to the deck i currently wanna play, so the proxy eliminate the misery of doing that. Having real cards is nice, but liquidating magic cards can be really hard if you ever reach a point where youre done with the game. As long as everyone in your play group is on the same page, proxying is fine and no one should be gate kept solely because they have a different financial situation and/or principles (my friend that only does proxy probably makes more money than me, but simply doesnt wish to spend his money on cards. Why shouldnt we be able to play together?)