You're very right that actually producing a Linux build in a lot of game engines is pretty easy. However, since the audience size is positively miniscule, and we still need to QA the linux builds at least a little bit to make sure they work properly, historically it has never been commercially sensible to do this. We still do it with lots of our games, for essentially political reasons. But it is not a sensible thing to do haha. Desire noted regardless! Thank you!