Valve didn't invent Proton. As far as I understand, it's just a fork of WINE. I think the only difference is that it contains fixes for Steam versions of games. For non Steam games everyone uses WINE. I'm sure Proton is convenient for Steam users, though.
Not actually owning games sucks, but find me a digital marketplace that doesn’t say that you’re only “renting” them or some other bullshit.
Since GOG and itch.io give you DRM-free offline installers of games, I believe that you do own the games that you buy there. I haven't read their ToS, though. It is possible that they say the same thing.
Steam doesn’t call it renting, rather, I quote, “As a Subscriber you may obtain access to certain services, software and content available to Subscribers or purchase certain Hardware”, where the subscriber is the word to call any user that has a steam account, nothing less nothing more: “You become a subscriber of Steam (“Subscriber”) by completing the registration of a Steam user account.” https://store.steampowered.com/subscriber_agreement/#1
Thanks for finding the exact quote. They didn't use that word, but to me it sounds like renting. You have access to software as long as you are a subscriber. But I probably wouldn't mind this if their games didn't have DRM. Then, if at some point you stopped being a subscriber, you would still be able to play your games (at least the ones you've downloaded). Another interesting thing is that they can ban you for selling your Steam account. But before Steam became popular, it was usually possible to sell used games.
Also, torrents do exist, and guess what, they’re DRM free, just as you like it, I assume. That’s actually exactly why they should exist, imo: to preserve things.
The point is that DRM is unethical. I refuse to pay for anything that contains DRM. Breaking it is illegal, requires special skills and sometimes it's very difficult even for experts (Denuvo). If those games were Free Software, any programmer could remove DRM from them and distribute such modified copy. That's exactly why we need to get rid of proprietary software - so that developers don't have power over users. I also think that piracy should exist, but it doesn't solve our issues with software freedom. Nobody should restrict what people can do with their software and their computers.