And nobody has ever demonstrated that this ostensible "dependence" has any adverse effects on Mozilla's policy.
And you're right, the non-profit-status doesn't imply that, they could just as well do the same as a commercial enterprise. It would be more obvious that way.
Would Mozilla make the step to ship an adblocker with Firefox? It would certainly be what their users want (the most popular extension by far being uBlock Origin), but it would pretty much decrease their worth to Google to zero, hence kill the funding. And there's your conflict of interest.
And perhaps you and I know how to disable an ad blocker selectively. An average user might simply see problems with websites and uninstall Firefox as "not working", tanking its marketshare even more.
So Google doesn't necessarily factor into that decision, really.
It very much could lead to the opposite too. "Oh hey, the web works when you're using Firefox". My mother has become a missionary (for adblockers, not firefox) since she's once witnessed how websites look on a friend's PC. She told her "I think your computer is broken", which lead to confusion & a presentation on my mother's PC... which lead to them calling me asking how to make her friend's PC do that too.
It might, ironically, also be a great signal for Google's bots. I've never seen a quality site that tried to block me for using an adblock, and even "hey, please turn adblock on" is a strong signal for me that it's SEO content and I should go on looking for something else.
