Yeah for older games not surprised. Wish there would be better support for legacy games like GOG does.

For older games, I'm using my old gaming desktop in the mean time but I might have to create a set up for Win 10 , gonna grab a iso before they completely get rid of 10.

Even GOG games are affected. Aka. Alpha Centauri.

The biggest thread to Windows is Windows itself. The stuff I've heard Microsoft is developing for Windows is the kind of stuff that could make me ditch Windows in a hearbeat, games be damned. This is coming from someone who's a Windows user only because of games at the moment, and I know a lot of my games already run on Linux - but it's just not enough at the moment, and it's not looking like it's going to change drastically any time soon. But Microsoft could make me ditch Windows anyway. Windows 11 has already been pretty bad, so I've little faith in Windows 12 improving things much - and it's sounded worrying instead of promising so far.

That said, I'm glad for the work Valve is doing to advance, well, Linux gaming, in practice. I'm not very optimistic about the future anyway, but it's a good direction to have, and it might not actually take all that much to make Linux a viable alternative. I bet that at just 10 % marketshare almost all notable games would get a Linux version as well. Well, 10 % is already as lot to ask for, but even at a much smaller marketshare, Linux support could drastically improve. Again, I'm not confident we'll get there, but it doesn't necessarily take a large screwup from Microsoft to make Linux gaming viable in the large scale. But again: Steam isn't the threat, Microsoft is. Valve is setting up Steam to be a viable option should a chance appear, but most likely Microsoft will have to provide the chance. That, or there's some other surprise development (e.g. Google/Android).

I haven't checked the situation in a while and the page you linked doesn't mention a version, but isn't that probably from an old version and not the version Steam Deck is running? The old version was based on Debian, which is mentioned on that page, but the Steam Deck version is based on Arch Linux.

I use Windows for work, a Mac for home computing and a Steam Deck for gaming. I would NEVER completely ditch Windows as it's by far the most reliable OS for 95% of jobs that actually need a PC.

I think the base premise that a large chunk of PC's are sold just for gaming is also questionable. Sure, gaming might be a main reason why someone buys a PC, but I can guarantee you that in 99% of cases it's also for other tasks as well. We live in a gaming bubble where it feels that PC's are used only for gaming, while Steam reports clearly shows that the VAST majority of gamers use fairly mid-ranged gaming laptops, laptops that they probably also use for their work or other hobby projects.

Would I get a PC with SteamOS? Sure! I LOVE my SD, it's by far the best purchase I made (gaming wise) since I bought a PS4 way back in 2016. Would I dump Windows? Absolutely not.

I'm not saying that.  I actually wrote:

I'm saying that of the gaming market, systems sold purely to be used a gaming machines.

So for the first part I reluctantly agree. I hope more game devs see in the statistics playing their games on Linux through Proton. But on the other hand it might be very comfortable for the devs to use Proton instead of a real native implementation. But that actually would suffice. For gamers it really doesn't matter that much if it is emulated or native, as long as gameplay is smooth, and for the dev it could be easy to make sure it runs smoothly through Proton.

For anti-cheat - these might be killed by Microsoft. Well, client-side anti-cheat, server-side works even if you play on Linux. The Crowdstrike desaster has MS eager to improve security and anti-cheat uses exactly the thing Crowdstrike is using, it basically hacks your PC and installs a root-kit. That is very dangerous as Crowdstrike has shown. On Linux there is instead an API for implementing such use-cases, so Crowdstrike there isn't actually installing a root.kit but using an API that Linux offers. MS is working to do the same and then banning all 3rd-party software from kernel-access. Which would either kill client-side anti-cheat or relegate them to these API, something which they could also use on Linux or can be easier emulated by Proton.

I recently switched from windows 10 to a linux OS on my retrogame dedicated mini-pc.
Man, it was quite a boost in terms of overall performace, responsiveness and on system resource usage (cpu%, ram etc).
Considering it is an open-source OS driven by the community and not tied to any particular company, I think it should become the way to go for gaming and new derived OS like SteamOS.

Windows updates tend to break old stuff moreso than new apps, so its not a surprise.

Hopefully a future patch will fix that, going by the source you provide in your first post, hopefully an update/hotfix will occur.

I had an issue with one of the apps I was using years ago, did a update on Windows 10 and it broke it, an update after that thankfully fixed it.

I guess the only thing you can do is either play the game on another computer or try using a Virtual Machine.

People seem to use their PCs so little these days for anything Windows-specific that I'm actually expecting maybe even most people to be capable of simply switching to Linux, if that option was presented to them as easily as Windows is. People use their phones instead for very many things, and things that have traditionally been native apps have been moving to the cloud. For work (which is a non-factor for gaming anyway), Windows is probably a very strong contender, official support probably being a major factor even if there was no Windows-specific software, but for private use, gaming might well be the only reason for a lot of people to keep using Windows (aside from almost every sold PC coming with Windows pre-installed, of course, which is a major factor, to say the least).

Admittedly I could be wrong, but my current bet is that the majority of private PCs don't actually need Windows for anything anymore, aside from gaming.

That is a good take. I do agree that you don't "need" Windows. I could do my work on OSX or Linux as an IT professional, but I have worked and the ease of use that I am accustomed to, makes Windows a default option. Most people won't want to learn several different PC OS's so I bet what works at the office is more than enough for home. And let's face it, no other platform really combines the ease of use for entertainment purposes and work as Windows does. 

I am not a fan of Microsoft nor Windows (hence why I use OSX at home) but the inertia is there for businesses and people and they won't switch, at least not for the next decade. Predicting over that timeframe is pointless. 

My point is that we have seen this prediction come and go with iOS, Android, OSX and Chrome OS many times before, and it never materialised, mainly because as far as cultural and economic impregnation goes, Windows is unrivalled.