Right and to your point, there's not a whole lot of precedent for browsers successfully funding themselves when the browser itself is the primary product.

Opera was the lightweight high performance extension rich, diversely funded, portable, adapted to niche hardware, early to mobile browser practically built from the dreams of niche users who want customization and privacy. They're a perfect natural experiment for what it looks like to get most, if not all decisions right in terms of both of features users want, as well as creative attempts to diversify revenue. But unfortunately, by the same token also the perfect refutation of the fantasy that making the right decisions means you have a path to revenue. If that was how it worked, Opera would be a trillion dollar company right now.

But it didn't work because the economics of web browsers basically doesn't exist. You have to be a trillion dollar company already, and dominate distribution of a given platform and force preload your browser.

Browsers are practically full scale operating systems these days with tens of millions of lines of code, distribued for free. Donations don't work, paying for the browser doesn't work. If it did, Opera (the og Opera, not the new ownership they got sold to) would still be here.