It’s all about Firefox OS
The fate of Firefox Marketplace and Firefox apps appear to be dependent upon how competitive the desktop version of Firefox can remain against Chrome, and, additionally perhaps, how successfully Mozilla can incorporate the store and future versions of Firefox into the Windows 8 app ecosystem. On Android, Firefox Marketplace comes off as a proof-of-concept demo -- a plaything you can tinker with. Ultimately, Firefox Marketplace will not matter most to the Android or desktop platforms, but to Firefox OS. It gives further hints as to how Firefox will function as a mobile OS.