Graphics layers are fairly stable, OpenGL still works, and Metal was introduced 10 years ago. The issue is that they switched the CPU architecture three times, from PPC to Intel to ARM, and dropped 32-bit support to make the ARM transition easier.
The question are: would Valve had still made a profit if it sell only 50000 copies pre-orders and then the normal copies? Probably yes. Would it be easier to Valve to make their games work on the current macOS? Probably yes, they had the updated CS2 already working on macOS, but then canned it at the last minute for the usual "no one will play it on Mac".
But Valve didn't even try, they ported Steam to macOS in 2010, ported a bunch of games to 32-bit, when every Mac out there was already 64-bit, and called it a day. They didn't even fix their store to properly show which game is 64-bit or not, or fixed their Steam Input to properly support controllers. They left the app half-broken and then complained they had not enough users. Steam is still a x86_64 app after 4 years of Apple Silicon.
On the other hand Apple didn't even care about games too much. So yes, no one really cares.
When Valve released Portal 2 in 2011, it was still 32-bit. This wasn't a problem for Windows users and still isn't. Valve tried as much with the Windows release of that game as the Mac one.
Mac is just an unstable platform. Developers either put up with it or get shown the door. Valve doesn't like to be pushed around by the platforms it uses, which is why they rejected the PS3 and began to prop up Linux as a viable alternative for gaming.
I have a 2017 Mac and loaded steam on it and yeah no other publisher is going to recompile their game for 64bit MacOS it seems let alone ARM64 so I think valve saw the writing on the wall.
I hoped that the recent 64-bit TF2 update would mean support would return to Macs, instead Valve explicitly removed support for TF2 on macOS :(
The only Valve game with official macOS support right now is Dota 2, which is x86-64. Once Rosetta disappears (whenever that is), there won't be any official Valve games available for modern macOS.
This is how I feel, I own all the Half-Life and Portal games on Steam, but since the 64 bit ARM transition they're just useless bits. And it feels like it shouldn't that big a problem to port them, but nobody seems to care enough.
The funny thing is that the Source Engine code was leaked years ago, so now it's possible to compile an arm64 native version of Half-Life, Portal, and more, without Valve help.
The question are: would Valve had still made a profit if it sell only 50000 copies pre-orders and then the normal copies? Probably yes. Would it be easier to Valve to make their games work on the current macOS? Probably yes, they had the updated CS2 already working on macOS, but then canned it at the last minute for the usual "no one will play it on Mac".
But Valve didn't even try, they ported Steam to macOS in 2010, ported a bunch of games to 32-bit, when every Mac out there was already 64-bit, and called it a day. They didn't even fix their store to properly show which game is 64-bit or not, or fixed their Steam Input to properly support controllers. They left the app half-broken and then complained they had not enough users. Steam is still a x86_64 app after 4 years of Apple Silicon.
On the other hand Apple didn't even care about games too much. So yes, no one really cares.