The majority of paid for DAWs are also missing (Bitwig & Reaper only I think), then on top of that the vast majority of plugins are not built for Linux either,

The majority of paid for DAWs are also missing (Bitwig & Reaper only I think), then on top of that the vast majority of plugins are not built for Linux either, additionally lots of pro-spec hardware doesn't have Linux support. Of course your argument still holds true, in that most users (especially here) won't be pro-audio users, but hopefully in time the support for pro-audio users will increase on Linux, because Apple and Microsoft seem to be making the experience steadily worse.