You’re coming at this from the perspective of someone who wants to set up a PC primarily in order to play games, and probably wants to try out every game under the sun. Of course, you’ll install Windows.
Try instead coming at the question from the perspective of someone who already has a Linux workstation (e.g. for work) and wants to do as little as possible in order to play a few games—maybe the ones their friends are trying to get them to play as a member of a team. Windows isn’t worth it here: you wouldn’t use it for anything else (so every time you boot into it, you probably have to spend two hours installing updates), and booting into Windows would also prevent you from multitasking to the Linux apps you rely on. Compatibility shims, if decent, are far more interesting to this audience.
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).
You're neglecting the crowd that have Windows at home and want to stop using it also. If gamers can have the exact same UX on Linux then that's one of the biggest obstacles to switching solved.
"People who own a Linux workstation at home and just want to play a few games" make up a disproportionately large amount of the developer-base for pretty much any software, though, including games. It doesn't matter if none of your users care about a particular feature, if a fair number of your own devs do.
Yeah, but for a piece of software to acquire Linux support, you don’t need the majority of its developers to own a Linux workstation and want to use the software with it; you just need a non-negligible amount (i.e. enough developers with the spare man-hours to get the work done.)
Sometimes, in fact, it only takes one or two developers. I can’t think of a good Linux example here, but I know of a good few projects (Dolphin, for example) where the macOS target is supported entirely by the one or two developers on the team who use macOS.
Quite true, my comment was more against the typical HN remark that "developers" only use GNU/Linux, as if the software for the two biggest desktop environments would appear out of thin air.
Try instead coming at the question from the perspective of someone who already has a Linux workstation (e.g. for work) and wants to do as little as possible in order to play a few games—maybe the ones their friends are trying to get them to play as a member of a team. Windows isn’t worth it here: you wouldn’t use it for anything else (so every time you boot into it, you probably have to spend two hours installing updates), and booting into Windows would also prevent you from multitasking to the Linux apps you rely on. Compatibility shims, if decent, are far more interesting to this audience.