Earlier quoted context omitted.
It's important to note here that Mozilla spends the majority of that money on non-Firefox projects (something that has pissed off people who have wanted to donate to Firefox specifically for ages). Firefox itself gets a sliver of that.
Like many you are likely confused by the Foundation (MoFo) vs. Corp (MoCo) finances. You can only donate to MoFo, and indeed it doesn't spend much (if anything) paying Firefox staff. This is because Firefox staff is on the MoCo payroll, which gets its revenue mostly from their search engine deal with Google. MoCo actually pays MoFo to use the trademarks that are owned by MoFo.
The relationship between Mozilla Foundation and Mozilla Corporation can make some details confusing. But most people who claim what they did never looked at Mozilla finances in my experience.