I've had multiple (typically but not always google) sites not work as well with firefox, as well as minor things like more captchas. I also don't want to worry and keep checking if my subpar performance on a site is because Google, a lazy dev or a lib didn't optimize for FF. Further, I just have a bunch of settings, extensions, saved password, history etc. already setup in Chrome.

Because Firefox is shit to use.

Adblocking means little if the actual browser is terrible to use. Between proper adblocking and a shitty browser, or a shitty adblocker and a shitty-but-still-usable browser I will take the latter because ultimately I have shit that needs to get done.

Practicality cares not for ideology.

Until recently, Firefox was an inferior browser, at least on macOS where it did a bad job of fitting native UI conventions, had a much less secure sandbox than Chrome, and was also behind in performance. Seems like things have improved on all of those fronts, so perhaps it's time to take another look. (That said, I've only ever used Chrome as a secondary browser for certain sites – my current primary one is Orion – so I have less incentive to experiment.)

A pragmatic reason for me: Firefox has been lagging a lot on my Windows machines for months, and I couldn’t figure out the problem. Tried extensive googling, even tried debugging it in the developer profiler to see if anything’s strange.

I’ve now given up, and switched to Chrome without regrets. I still miss Tree Style Tabs, but the sluggishness isn’t really worh it.

I’ll start using Firefox again until they fix this issue and realign their funding towards actual better engineering & performance instead spending on vanity “activist” projects.