They're looking to the future, not what is possible but what should or could be possible.
I'd much rather have Mozilla working on an "OS for the web" than Google, despite whatever problems Mozilla may have.
In this context, one of the problems that Mozilla has compared to Google is money.
Honestly, for all the money Google has, Google+ isn't very impressive.
Interestingly, about half of that 100 million comes from Google to secure their spot as the homepage and default search.
It seems to me their mandate is to make everyone's lives better. This looks like a project to define web standards for the future. It also looks like they've got enough to last them for a bit.