The key contribution of Android is that it created a Linux-based OS that is friendly to proprietary software and it does have decent proprietary software.
Desktop Linux users also want AAA games, Photoshop, MS Office, etc.
They just do not have them (Steam brings some hope) and have to live with shitty open source alternatives.
Firefox OS's position is somehow strange.
Yes, ZET Open's price is OK for developing world.
But does developing world have decent mobile networks?
Does developing world have decent HTML5 eco-system?
At least in China, IE6 usage is surprisingly high and most Web sites do not bother to support Firefox well (glitches are here and there), many Web sites are still IE-only.