It's unfortunate that after those changes, the Mozilla team did not take criticism in public forums very seriously and brushed it off as noise. I personally sto

It's unfortunate that after those changes, the Mozilla team did not take criticism in public forums very seriously and brushed it off as noise. I personally stopped using Firefox after some of those "architectural" changes started producing "dead" tabs - the tab could not be interacted after load. In place of "We're listening", users that complained got a "Works fine on my machine" bundled with a few rude words in places like Reddit. Not the core teams fault, of course. Someone with more time can probably set up a scientific test of the performance claim even today - set up a bunch of Selenium tests to open JS-heavy sites in multiple tabs on older versions of FF upto current version using BrowserStack or SauceLabs.