I'm pretty sure I saw some ChatGPT ads on Duolingo. Also, never forget that the regular dude do not use ad blockers. The tech community often doesn't realize how polluted the Internet/Mobile apps are.
"Wasting resources on making even smaller special purpose web browsers integrate with the engine is not a move for a company that has been struggling with a lack of independent funding for years now."
So says the narrative. Mozilla has money, but prefer using it for C-Level salaries : Mitchell Baker raised her salary from 2.5M$ to 7M$ within 4 years, all the while laying-off developers and spending a shitload of money on seminaries and others BS expenses. Meanwhile, the market share of Firefox dropped.
And I assume you have noticed that privacy is not their main concern.
Such a pity because Phoenix/Firebird/Firefox brought a lot to the Web. But I guess this happens when Corporate people take over any organisation.