It runs them now, but none of those games ran on Linux when they first launched. Grid Autosport took 17 months after the initial release, Mad Max took 13 months, Tomb Raider took 3 years (and the 2015 sequel is still not available on Linux) and Deus Ex MD was the only somewhat timely one at 2 months (but the previous game in the series was never ported to Linux at all).
I know not everyone cares about playing games the moment they come out, but many people do. Especially with multiplayer games where the community is most active closer to launch.
You might consider saving that money instead of promoting Linux through buying games you won't play.
Compound the interest, and maybe you can find an indie game studio investment instead. That would be a real and substantial contribution that moves the needle.
https://www.gamingonlinux.com/articles/looks-like-the-linux-...
And then, there are runtime considerations like where you store the player data, cache files, and the case-sensitiveness of the filesystems which many Windows developers are completely unaware of.
So no, Vulcan doesn't give you "zero effort" Linux ports.
Dunno, my Steam Box runs games like Grid Autosport, Mad Max, Tomb Raider, Deus Ex etc. without a single issue, as fast as on Windows (quad i5 + NVidia), and I don't even notice I am on Linux. So thanks to Valve and Feral Interactive, I can slowly move away from Windows to Linux for all my computing needs, not just for programming, Deep Learning and blockchain. What else is missing?
Moreover, I can run a lot of software under Wine, like Adobe CS6 or MS Office, or even many games (it has gotten significantly better lately).