What is really interesting about Linux users is that they cost an enormous amount in support.

I think it was a dev of the reboot of Planetary Annihilation that said their Linux users / build made up a few percent of the sales but over 90 percent of all support tickets (!). Mind you that this was before Valve's Proton.

Edit: It was <0.1% sales but 20% of all support tickets: https://xcancel.com/bgolus/status/1080213166116597760

20% of auto-reported crashes. So it's not like Linux users were writing more tickets but the game crashing on Linux more (because of gfx drivers).

Yes, and I think a free-version user might produce more support requests than a commercial user for two reasons: 1) commercial/professional users might feel more entitled to support, but typically have a better understanding of linux and more versed in fixing stuff themselves. -- and more importantly -- 2) They probably have a dedicated setup where they can run the AMD-blessed distro

If those bugs are only present in the Linux port, then yeah, Linux users cost more to support. But if a significant amount of these bugs affect all platforms, then you could argue that a Linux user is much more valuable to them than a non-Linux user because they provide better feedback. Assuming they actually care about fixing their product.

Would you rather that the 100% of bugs in those 20% of tickets never got fixed?

Linux users write highly detailed bug reports because it's the only way to get things fixed without coding the fix yourself.

I don't think gaming on Linux is comparable here.