I don't think people in general realise how big a jump it was. Process isolation demonstrated that a browser with a single event loop is not a given, and the idea of completely separating page loads from page renders was, for want of a better term, a true paradigm shift.
V8 showed that JavaScript didn't have to be disgustingly slow. I still remember the "Chrome Comic" booklet. Google made a big deal out of having hired some of the best compiler optimisation experts money could buy and pointed them towards a goal. V8 came out with two decades of hard-core, bleeding edge research behind it.
It took Mozilla nearly a decade to catch up with multi-process Firefox (ironically, the project was called "Electron"). Chrome had the benefit of being a pure greenfield project. Firefox had to retrofit a completely different processing and rendering architecture that broke pretty much all previous assumptions.
I recall writing a note to an internal Nokia-infused thread that "Chrome's process isolation is an idea too good not to steal". At the time I didn't know just how damn hard that would be to pull off without introducing multiple flag days. In the end Mozilla managed with one.