Two decades ago, we at KDE always said that 5% was the magic number. If we got to 5% market share on the Linux desktop, then commercial games, applications, etc. would directly target it rather than ignore it. The steamdeck is wonderful, and if you include it, Linux is at about 3% right now. But it actually caused a huge acceleration in game adoption. So gaming is now ahead of that projection. Applications (i.e. Photoshop) probably still need 5%. Although we made that projection two decades ago, so it may no longer be valid due to cloud apps.
(I’m no longer involved with KDE, but was for a decade. It was an awesome decade.)