GOG

I can sort of understand why GOG has no Linux client. Have you noticed how there are differences among the distros? I use Arch (by the way), another Linux user uses Debian, the other uses Slackware, the other uses Enlightenment OS, the other uses RHEL, and so on. There are lots of flavors, structures, package managers, display managers... Some distros still use X11 instead of the newer Wayland... How to deal with so many differences? Whereas a Windows system is generally not so different from another Windows system regarding filesystem structure (i.e. where's Program Files, where's the system registry, where's the system32 folder, and so on), so it's easier to make a Windows client.

And then, there's a second reason why GOG may have no Linux client: Linux users often won't need training wheels. I bought Terraria from GOG, a game that I already had "purchased" from Steam a few years ago. I got surprised how easy is to install the game. They deliver a shellscript, you run it, you click next, next, tick accept, next, optionally choose another folder, next, wait, finish, and that's it. The thing just... works. Why bother to install a whole client when the current way already works seamlessly? You won't even need internet connection during the installation, whereas a client would require it, so in a sense, IMHO, a client would actually worsen the experience of installation.