> What about Linux? Steam has supported Linux since 2013, and is notably the only big store that does.
Steam is a big contributor to making games run on Linux but it's not some magical sauce unique to Steam. Unless you're talking about the store client software itself having better support, I haven't used any of the first party store clients on Linux. My GOG games run fine on Linux with Heroic Launcher.
But the bigger issue for me was when I bought older games from the Steam store only to discover that they didn't run properly or at all on Windows 10 despite the statement that they do. I bought them again from GOG who actually patched them to work. Supporting the OS I bought the games for should be guaranteed unconditionally for as long as I own the game. Support for additional OSes, especially when it's best effort, is just a bonus not a replacement.
I'm talking about his complaint that Steam does not have any contingency plans for running games on old hardware due to them not supporting old versions of Windows. You can install Linux on that hardware, so I'd say that's a good enough contingency plan.
* Assuming that game is supported on Linux
While compatibility has improved a lot, it's difficult to argue it's on par with a game on as-released hardware + OS.
There will always be gaps or altered functionality in compatibility.
And unfortunately, because of the recency bias of popularity, there won't be large enough player bases to justify corporate fixes.
It needs to be a priority despite finances (e.g. GoG) or community driven (e.g. Kaldaien and the moding community).
And it seems fair for the latter to be pissed off when Valve intentionally creates extra work for them, because either Valve doesn't care or it makes business sense for them.
And if nobody cares... troublesome games just disappear. Which seems tragic.