There are tons of reasons my dude. You can still have platform-dependant technologies in your game even if the base engine itself supports linux.
The kernel in use is literally meaningless. Sony’s userspace is unique and the graphics stack is fully proprietary. Same for Nintendo.
I find that to be an annoying thing with Japanese software in general, gaming or otherwise: more proprietary garbage than Western software and practically hard-coding it to 100% force you to use the software in the way THEY intend for you to use it, not how YOU want. Makes for worse Linux compatibility at best, if any at all, compared to Western software. Note that I’m purely talking about native or straight Wine Linux compatibility, not Steam/Proton, which works around those issues well.
In an ideal world everything would work out, but for some business it is a pretty huge commitment for what was less than 2% of the market just a few months ago. We certainly lost money porting our game in Linux at that last place I worked. It was before Proton though. Obviously each case is different, and some games work on Linux out-the-box due to Photon so this become a non-issue.
From my own experience, “not bothering” is definitely the better business practice since chances are you won’t make back the development costs.
Maybe Steam Deck and that porting library have improved things but a decade ago it would have been better business to just give Linux users $20 to not play your game.
I believe the PS5 is partially based off of FreeBSD and I don’t think there is as strong of a gaming scene on BSD (even relative to the size of its userbase). I feel like there would be some rather large leaps going from a tailored console OS to a more widely available alternative OS.
