In fact I would visit https://arewee10syet.com every couple of months and sigh for years wanting to switch back.
On Firefox I used to have hundreds of tabs open and no visible ui chrome most of the time, just vimperator/pentadactyl and usually hidden treestyle tabs. Along with a rotating collection of adblockers and privacy extensions.
These days? I just use Safari on a Macbook with Content Blockers (https://webkit.org/blog/3476/content-blockers-first-look/). My battery lasts double digit hours and everything is always snappy. Readability and integrated 'read it offline later' mode is a cherry on top.
Ultimately I think we forget that with Flash being truly dead and buried on pages with no junky javascript trackers even a NeXT computer, far less powerful than your phone, should be enough.
And all the browsers are now able to limit the damage a heavy/crappy page (like gmail) does to its own tab.
tldr; And Jesus wept for there were no more worlds to conquer.