Pay about 1000 employees and host a ton of infrastructure for a bunch of open source projects (including of course Firefox, but also things like Rust, Valgrind, Opus, etc.).
I am not talking just about projects, but about cash in the bank. Once the funding stops you should have enough funds to bridge the gap until you find the next big project. Hopefully as great as Firefox and Rust are. Kudos to Mozilla!
Yes, in principle they should be able to put away enough to operate in perpetuity (albeit on a small budget). It would be interesting to know whether it's happening, presumably the finances are public so it shouldn't be too difficult to to find out.
2.6 million per employee? And infrastructure hosting, especially just for bugtracker / source repo / CI cannot be that expensive.
At that, what are the employees doing? Rust is fantastic and important, but Opus has been pretty done for years, Daala is still DOA, isn't Xiph an independent organization?
I think you made a rather basic maths error, it's 375k per employee.
Firefox still gets an enormous amount of development effort. I think people don't notice because Chrome likely just gets an order of magnitude more.
Xiph is independent but I believe Mozilla employs all the core developers. They're currently working on doing for video codecs what Opus did for audio.
I actually think Firefox is currently seeing more development than Chrome and it's just not as noticeable, because a lot of that development goes into unearthing some of the technical debt that they have (Electrolysis for multi-processor integration, WebExtensions for a proper, stable add-on API), or is an investment into the far-reaching future (Servo).
That being said, I'm not actually that well informed about Chrome's development, so it could also be that I've simply missed some of their development plans...