Power users in general will dsable telemetry, so the bulk of the data these companies get come from the patterns of usage of the lowest common denominator users. It's no surprise then that everything that appeals to power users is slowly but surely removed from future iterations of the software in question. Mozilla is just another dumb corporation circling the drain of death at this point.
In my experience, people often make decisions first then go trawling through sea of data, selecting metrics which support their decision and ignoring those that contradict it. Intentionally or not, much of this stuff is essentially p-hacked.