I mostly agree, and don't get all the fuss about Chrome (or any other browser's) UI. To me they look all very similar and function very similarly. The differences just don't seem that big of a deal. I think it is mostly people being resistant to change. I had one friend that I convinced to switch to FireFox after a year[0]. A month after he switched over I got him to admit that it was easy to switch and there's no real change.

  >  it took a week of tinkering 

I wish this was more obvious, but there is a user.js file that Firefox looks at[1,2,3]. You can edit this and carry it around in a dotfiles or something.

  > They really need to get out of this stale and boring state and innovate more

I'm just as excited as you are for side tabs, but I don't think browsers need to be constantly innovating their UI. In fact, the last time Firefox did that it took a week of tinkering to get it back to a usable state, and I now have the constant "Compact (Unsupported)" layout hovering over me, reminding me that one day I'll probably have to tinker even more.

I use the browser for at least 8 hours a day, I don't need the experience constantly changing, it's a tool. "stale" and "boring" is also "stable" and "dependable".

[0] Argument is about having legitimate browser competition and the privacy boost of containerizing what data Google could (keyword) collect. I'd really only bring it up when he'd be complaining about Chrome or Google, so quite often.

[1] https://support.mozilla.org/en-US/questions/1197798

[2] https://kb.mozillazine.org/User.js_file

[3] https://support.mozilla.org/en-US/kb/profiles-where-firefox-...