Windows and DOS games started working well later, as WINE and DOS emulator were evolving.
But Linux had a thriving gaming scene of its own:
- You’ve already mentioned Loki who made native ports.
- Another type of “ports” were game engines made from scratch that used the level files of the original, games like Doom, Transport Tycoon, Caesar III, Panzer General, Stunts, ReVolt etc. You had to own the game files but the executable was FOSS.
- There were lots of cool native games, many shooters (Warsow , Nexuiz, Cube, Tremulous), strategy games, cool arcade games (Tux Racer, Atomic Worm, H-Craft, Droid Assault), the rogue genre which debuted on UNIX and had tons of variants and so on.
I’m only a casual gamer so this is just stuff I ran across occasionally, there was probably more.
Spending 20k to unchain yourself from a clearly ill-meaning vendor can be seen as a good investment in itself. 5k saved in (recurring) fees is a bonus.