I'd consider buying stuff if I could play a demo on Linux. If there's a demo then at least I know that it runs, plus I can see if it appeals to me or not.

I just deleted my Steam account after about 3 years of having it and I feel indifferent about games at this point. In the future I might return to gaming with Origin, Windows Store or maybe a console. At the moment I'm on Fedora.

Not sure if it'll make any difference in that case, but here:
https://www.gog.com/games?sort=popularity&page=1&system=lin_ubuntu,lin_mint,lin_ubuntu_18&price=free

A bunch of Linux demos plus a few 100% legit free games.