I think you're misremembering or you didn't try Safari at the time. The first version of Chrome was not very different from Safari which it was just a shell of anyway.
V8 kept getting even faster, including adding faster RegExps, which pushed the other browsers to speed up their JS too. Firefox is now using that RegExp implementation too, even if they're not using V8.
WebKit was itself a fork of the KHTML browser engine. And just like WebKit diverged from KHTML, Chrome diverged from WebKit.
The main reason I stuck with Chrome was the tab isolation. WebKit was super crashy back then, with Safari crashing several times a day just browsing the web. In Chrome only one tab would crash instead of the whole browser. This was one of the original selling points in addition to performance.
I switched back to Safari when I got my first Retina MacBook Pro, since Chrome had terrible performance in HiDPI for the first two years of retina Macs.