FF has always been security conscious and was actually the big dog until around 2007 or so when they had to do a full rebuild of their code and this made it so that a lot of peoples’ favorite plugins stopped working until they were updated. This coincided with when Chrome started to become bigger and people switched. Now people are switching back. I use a combination of FF and Opera GX.
FF was definitely the top dawg through the last half of the aughts. People got frustrated with the constant updates. Chrome had a lot of hype and for a while was the slick new browser. It didn’t take long for it to get just as slow as FF used to be, but now more enterprise web-apps will cripple compatibility on non-chromium browsers so it doesn’t matter how good FF gets.
I was one of the users who left because TabMixPlus stopped working. Never worked again, so I’m with Vivaldi. I know; it’s built on Chromium, but being able to have my tabs on the bottom of the window is worth it for me.
I use waterfox (firefox branch) and it has that as a default option https://imgur.com/oWzCeA7
I seriously miss tab mix plus.
IIRC they switched to webextensions in Firefox 57 in 2017. Even before that it was never the browser with the biggest market share, and Chrome had already got a huge market share in 2017.
I’ve been using Phoenix/Firebird/Firefox as my default browser since 2003. Never understood the appeal of Chrome.