Google pay Mozilla hundreds of millions of dollars each year to place Google as the default browser. It's by far their biggest income stream. In 2023 it was reported as 75% of their revenue.

There's no world in which 75% of your revenue coming from Google doesn't influence what you do. Even if it's not the main driver of all decisions, pissing off Google is a huge risk for them.

There's proof of financial dependence, here's a recent report https://assets.mozilla.net/annualreport/2021/mozilla-fdn-202...

In 2021 they got $500M "royalties" (this is their payment from Google) with only $75k revenue from all other sources, including $7.5k donations.