That's why x-platform isn't has little support, no one really cares about mac/linux as much as windows.
Why should they?
Apple decided it for themself to make a monopolistic closed OS, now they have to bite the apple they hatched.
And linux, no mather how much buzz they get, is still a tinkering OS as getting full hardware support running is a no go on most systems, haven't seen one where all the drivers where existing and worked without serious tweaking of system settings ...
So why support them? they have enough to do to make it a full desktop OS before they need some stuff to "play" and "take offtime" ...
beside that, casual gamers use Windows and OSX, not Linux, I fear ... So do the devs creating casual games and tools / libs to create such.
And no, please don't tell me BM can be used for serious applications. The UI module still needs a core rewrite to be taken serious, right now I'm forced to use PureBasic when I want UI stuff that works crossplattform and that does not just "pretend to do so"