I'm building a gaming computer at the end of this year and I'm strongly considering just throwing linux on it instead of windows as well, because if protondb is to be believed most games run perfectly fine on linux these days.
Let's forget for second that iOS (until 2015), Android, Switch and PlayStation have some POSIX like support and with exception of PS, all support OpenGL in some form, yet most of those studios couldn't be bothered.
i see a potential future where microsoft will port windows to run on top of a unix kernel. small chance, but not impossible.
those studios won't bother with native linux support until a sizeable amount of users play their games on wine. and that numer is growing. which is the point.
"Half an operating system: The triumph and tragedy of OS/2"
https://arstechnica.com/information-technology/2019/11/half-...
The section "A better DOS than DOS, a better Windows than Windows" is worth a close look and introspection about what WINE/Proton effectively bring to the table.
for one, linux does not have a single business interest driving it, so many of the OS/2 issues relating to IBM don't apply.
being a better windows than windows bolstered windows apps, but only killed OS/2 because native OS/2 was worse than native windows. that too does not apply to linux.
OS/2 died because IBM expected it to be backed by microsoft, and gave up when that didn't happen and they realised that it could not compete. linux never had this issue. linux won't loose its backing. linux never depended on being able to compete against windows. microsoft is now supporting linux more than it ever supported OS/2.
so at the worst, the status quo remains, and nothing changes. realistically though, wine will keep getting better, enabling some people to use it. wine will continue to be developed and supported. there is no risk of that ever stopping. there is no danger betting on wine, because once it works, it will continue to work indefinitely. at worst wine may fall behind implementing some new windows feature that new apps need, but it won't stop supporting what already runs.
wines user share is not going to go down. linux and wine development will not stop. unlike IBM we are able to play the long game here. there is nothing to loose. there are no risks to continue as we are.
however if you look at english steam games only, the value is actually 2.5% and the overall trajectory seems to be slow growth:
https://www.gamingonlinux.com/steam-tracker/
let's see where we are next year.