The biggest problem isn't the small market share (3% of desktop users is still a decent chunk of customers), but the lack of standards and fragmentation making good QA basically impossible.
This isn't relevant to game developers. Most game developers who nominally support linux will test on a single distro and release a single zipped or tarred binary (not even an rpm or a deb). Linux users are expected to sort out any issues they might encounter on their own distro, and linux users expect to do this as well.
So for example, I as a linux user download factorio_alpha_x64_1.1.91.tar.xz
This isn't a package made specifically for my distro. Was it tested with my distro? Almost certainly not. Do I care? No, not really. Might I have some trouble with it? Probably not, but maybe! Do factorio devs get flooded with hate mail for not packaging factorio as an RPM and testing every single release with every single long-tail distro? I think they don't. They might get a few nutjobs sending them letters but by in large the linux gaming community (as it were) has low expectations and is easily pleased with the bare minimum.
>Do factorio devs get flooded with hate mail for not packaging factorio as an RPM and testing every single release with every single long-tail distro?
Based on my experience (not game dev), Linux users are extremely polite, grateful and willing to bend over backwards (or even write patches themselves) to get things working.
This makes it even harder to tell them that you simply can't support their preferred configuration.
This is the factual reality of the matter. 300+ distros to test and you can't support them 100% of the time like you can with Windows or macOS and give a guarantee to your customers that it works on your OS.
Unfortunately, the Linux fans continue to ignore the worsening fragmentation issues.
Steam includes the Steam Runtime, a container-like environment that provides a single target for Linux game developers. In fact, it's commonly used by NixOS users to run proprietary software that wasn't built for NixOS.
Other than the Steam Runtimes there is also Flatpak as a container-like environment to target if you want a stable environment that is shared accross distros if you aren't specifically making a game that is published on Steam
Yes, but that's a very broad brush. Regardless of the distro people use either x11 or Wayland, this compositor or that compositor or no compositor, this or that driver, ....
So even if you manage to publish a deb, rpm and to the aur, QA is difficult.
The biggest problem isn't the small market share (3% of desktop users is still a decent chunk of customers), but the lack of standards and fragmentation making good QA basically impossible.