If one means “I can play 90% of games” or “I can play games at 90% the performance” or “I can play games but no recent multiplayer AAA titles” etc. then yes it’s a viable platform. But you need a big bag of ifs.
While there is great progress bringing gaming to Linux, it’s more and more looking like it’s going to make the bulk of games better while the biggest titles get even further from parity.
Reasons include
1) to play a AAA title you need a specific graphics driver built for the game where nVidia and AMD have made fixes and optimizations for the specific game. On windows this driver is obviously released in tandem with the game
2) An anticheat for a multiplayer FPS these days is a kernel level driver or more and more resembling a root kit. Not only are these not existing on Linux half of the time, the same type of person who prefers Linux usually doesn’t approve of these things being on their systems either.
So: gaming on Linux has advanced in the broad middle of games. Lots of titles now play “ok”. But is gaming on Linux really any closer to being a windows replacement if the biggest titles are still completely windows exclusive?