People who own a Linux workstation at home and just want to play a few games is vastly outnumbered by people who own a Windows desktop at hone and just want to play a few games. Probably at least 100 to 1. And the former group, with the “almost works” compatibility, will be a much bigger maintenance burden per customer.

Heck, I’d bet money that the Linux casual gaming crowd you described is also heavily outnumbered by people who have a dedicated Windows gaming PC (e.g. me, Mac user otherwise).