No knowledge of the business. But I think it's because of the underlying question that plagues Mozilla: How will that make money?
it's a completely obvious "problem" -- more users are easier to monetize, even if they "simply" go the Wikipedia donations model
many people stated that they are happy to do targeted donations (ie. money earmarked strictly for Firefox development only, and it cannot be used for bullshit outreach programs and other fluff)
and if they figure out the funding for the browser (and other "value streams") then they can put the for-profit opt-in stuff on top
Google pays Mozilla, Mozilla has more money, Mozilla spends more money (especially in compensations to a bloated C-level), Mozilla needs more money, Google threatens with paying less, Mozilla will lube up and bend over.
They don't really need money. Look at Mozilla's CEO compensation for example. It was 7 million USD in 2022. Seven. Million. For ruining a bastion of the open internet.
The problem is the MBAs.
I'm not sure how well know this is, but besides their contract with Google to be the default search option, Firefox does earn money through revenue share with all other default search options. A normal healthy company would just rely on those. Growing the user base would therefore grow the amount of rev-share income. So improving the product by itself, and thus attracting users, does make money - and probably enough to run Firefox and Mozilla. Just not enough to pay their CEO.