Firefox OS was never a real product, but a PoC.
IMHO, Mozilla should absorb the Tor project and focus on Free Web technologies, e.g. a really Free email service and a Free cloud storage service.
Yes, I intentionally use capitol F for Free.
How to raise money? Freemium model.
A good email+cloud storage service, with the optional pay model for using a custom domain.
And stop attacking the Linux distros for the Firefox trademark (forcing them to create the Iceweasel fork) or including proprietary services (e.g. Pocket) forcing the creation of the Icecat fork.
Just be a Free and Open browser, with some good cloud services, and make money within a Freemium model (allowed by Free Software Foundation policies).