For Mac development you need a Mac to test the game on.
(If you think that you dont need a testmachine, then you are not taking the development seriously anyhow)
That limits the userbase quite a lot (a big argument for not investing into it)

Linux is cool, but not a musthave for development.
(a "tested on and optimized for Wine" sticker can be a workaround if you really must have it working there too)

Mobile development is a totally different playfield, tech and preformance wise.
Most here cant even make a game on the PC without some impact on FPS.
Dont want to imagine how it would run on a smartphone.

Its a different approach. I dont see the advantage of the gamestudio concept or tools for mobile development.
It would have to be totally different then, wich
basically is just wishing for a new gameengine and toolset then.
But there are tools out there already for that purpose for quite some time..