Some do, some don't. Probably down to whether someone at GOG felt like bothering or not.

Prehistoric 1 and 2 on GOG have Linux installers, which ship Dosbox and run via it via desktop file and start script as usual.

My guess is it is mostly due to rights issues. You know you can always download the Windows version and unpack that and set the game up yourself.

Yeah, it's primarily due to whether the publisher has accepted GOG offering a package for Linux.

GOG likely asked them (we'd like to offer packages for Linux and macOS, with no cost or extra work from you, and you might even earn a few bucks from users of those systems, would you agree to us doing that?), and was given a negative answer (no, we don't support those systems, and none of our customers use them, so don't).

Yeah, losers should learn to use Steam and Windows like every other gamer out there. /s


<fairly happily gaming on Linux and obviously using GOG, and a bit of Steam too>

Was it Innoextract you needed to unpack GOG's installers? I never bothered myself. Setting up DOSBox for the first time may take a while but it is not rocket science even if not just click click done.