A lot of Mozilla's money seems to be spent on executive pay, overhead, and questionable side projects. Not so much (or not enough) on browser development, it seems. I'd MUCH prefer Firefox to be a product organization with its own budget and perhaps a yearly contribution from Mozilla. I have more faith in Firefox than in Mozilla.
1) The nonprofit Mozilla foundation
2) The Mozilla corporation
The foundation owns the corporation.
The corporation develops Firefox and is primarily funded by the Google search deal. It also develops pocket and the VPN and gets some funding from their sales.
The foundation is funded by grants and donations, both from individuals and from other organizations (including from the corporation).
This goes to the Mozilla Foundation and not to the browser's development. As far as I know there is currently no way to donate to the browser's development.
Electron is also popular and Mozilla could produce a Firefox-based alternative (whose selling points could be performance/memory usage/battery life) and provide commercial support.
Is it going to sustain extravagant salaries & bonuses for the C-suite? Debatable. But it can absolutely be a suitable business paying reasonable salaries.
Isn't that a lot like saying "those sausages with toothpicks in them at the supermarket" are not saleable products?