Step 1 is get rid of the for-profit corporation that pays its CEO 2.4 million dollars a year to lose market share. That's 24 well-paid developers, or double that from lower-income countries.
The foundation had a revenue of $441 million in 2020. We know that in 2014 ~90% of their revenue come from its search-engine deal with Google. That means that without Google they'd have ~44 million to work with these days (or more).
That's a lot of devs, before even considering non-search-engine sources of revenue. Personally I don't mind ideas like the VPN. I do mind the stupid grants the foundation does unrelated to a web-browser or acquisitions like pocket.
How many years of Google money would it take to support ~500 staff purely for making Firefox in perpetuity? That's maybe ~$50 million/year?
This[1] says endowments target ~7.5% annualized returns. So a very conservative 5% return could pay for ~500 staff with ~$1 billion in Google bucks.
[1] https://www.nacubo.org/Press-Releases/2023/Higher-Education-...
That's a stretch even if we don't count the additional overhead.
Try > 5.6 million. https://assets.mozilla.net/annualreport/2021/mozilla-fdn-990...