You can certainly play a number of popular and/or high quality games on Linux, but it's hardly ubiquitous. If you're interested in a given specific game I would say your odds of it having a viable Linux experience are worse than 50/50 yet, and if it's a AAA title I'd say it's closer to 10-25% IME.
If not for Valve/SteamDeck this would be even more dire, and many of those experiences are still emulation-based i.e. Proton.
If you want to be able to play any given computer game being sold this year, that's only reasonably certain on Windows. Gaming is the only reason I still have a Win10 install.