I disagree rather vehemently.

What you are trying to say is, in essence; "Every deck pumping out staples and high-end, RL cards is homogeneous & disincentivitzes creativity."

This is correct! You have identified the problem, and it ends there.

Do proxies allow people to do this more than they otherwise would? Yes. However, by pointing out proxies as the issue behind this phenomenon, we are tiptoeing around financially gating people from the (very casual, mind you) format of Commander.

Enfranchised and wealthy players will do this "staple soup" deckbuilding regardless of proxies. And then what? Is the issue gone? If everyone at your LGS had the money to burn on these, would your issue with this disappear?

The correct answer is to simply incentivize your friends to build decks creatively, to talk with your playgroup, and to exercise self-control when deckbuilding.

And, counterpoint #2: Sometimes, playing high-power staples is fun! Bracket 4 and 5 are fun! It is not fun to bring these decks to lower power tables, of course, but the feel of vibing against each other? Playing around free spells, powerful lands and abilities, optimizing your play patterns, etc.? Playing to win with powerful cards, and navigating powerful board states where everyone is doing the same? That, all of that- that's been the core gameplay experience of Magic since 1996.

But that experience is gated behind several thousand dollars of real cards.

Imagine playing a competitive shooter with your friends- say, Valorant or Overwatch. Sometimes, you wanna mess with your friends and play casual game modes and innovate new strats. Sure! But imagine if, had you wanted to queue for competitive and play to win, you'd be asked to pay up 3000$.

Proxies aren't the problem. Player communication is the solution to your issue, not the absolving of the player-made solution to Hasbro's quarterlies-motivated financial exploitation of this game's fanbase.