First, old firefox (pre-quantum) really started to be slow and non-competitive.

Second, Google actually were caught on making their resources work worse on firefox and other competitors with some hacks.

E.g. https://www.zdnet.com/article/former-mozilla-exec-google-has...

Assuming that literally everyone use gmail, youtube, etc - it had looked that mozilla doesn't work reliably for end users.

I switched for that exact reason - Firefox was starting to become really slow. After a few years of exclusively using Chrome, Firefox (thanks to Quantum) became my default browser again. It still sometime feels slower than Chrome, especially on Google sites (YouTube and GMail are incredibly slow). But that could just be my current pc starting to show its age.

I've heard this a lot. I use youtube fairly regularly with firefox, and have never noticed any performance problem.

Chrome was also much more secure and didn't lock up as much thanks to process isolation.

Chrome was waaaaaay faster. It made Firefox look like a student project. I held out a lot longer than all of my laymen friends, but the gap eventually was hard to ignore.

There were also a ton of innovations that caused real quality of life improvements that it took firefox an incredibly long time to catch up to, like process isolation preventing a single misbehaving tab from crashing your entire session.

I can’t speak for the users of other OS, but for a long time Firefox was essentially unusable for me on OSX.

I have always liked Mozilla though so kept trying builds over time, eventually leading up to Quantum the nightlies became better and better and it was easy to switch back at that point.

What a shame it happened in the first place though.

Other than the performance, I think Mozilla changed their focus to browser based mobile operating systems and starved Firefox from developer talent.

I moved because Chrome shown a nice promise in speed, standard support and features, it seemed a good move. Same move I did back in the day when Microsoft released Internet Explorer 4, it was so good in comparison with Netscape 3-4 than it was too late when i got tired of it.

I've never used a Chromium-variant as a primary browser. Used Opera until they switched to Chromium and their Presto-based brower became untenable, then switched to Firefox.

Chrome had v8, it was fast. Forefox sort of got left behind performance wise.

You could still have a million tabs open, something chrome struggled with, so it kept some users.

But it took quantum to get users back.

Yes, my experience resumes like this: breakthrough browser, adoption, bloating experience, adopt next fast breakthrough browser.

The devtools really were ahead of any browser.

For the average person it was so much faster than ie 6,7,8,9 and google pushed it everywhere.

It comes default on android helps.