I was a Firefox user at the time (was using it when it was Firebird). People were already starting to shift away from IE towards Firefox at the time. A sequence of events where a person's computer was infect with malware, they asked a computer savvy friend for help, the friend "fixed" it, installed Firefox and told them to stop using IE is how most people switched browsers in those days. But Firefox was a slog and Chrome was a breath of fresh air when it was first released. So the sequence was tweaked to "install Chrome and tell you to stop using IE".
Chrome became what it is because Microsoft had tried to neuter the internet because they saw the web app potential and understood that it could undermine Windows market share. And when they realized that there was no stopping the internet, they spent several years incompetently trying to improve IE (and eventually Edge) before eventually going the "can't beat em, join em" route.
However, Google was smart enough to know that being superior doesn't count. Firefox was not horribly slow, the leap from firefox over IE was massive. Chrome over firefox wasn't quite the same leap.
The average user has been pushed aggressively, they weren't going to do research on web browsers when they even didn't know what a web browser is. Google knew that.
Chrome didn’t. It was noticeably faster and more reliable.
Switching browsers isn’t something that people generally do lightly. You lose them, you lose them for a decade+.
That and Mozilla behaviour hasn’t been great over the past several years; like, forced advertising extensions, crypto, more advertising to turn off on a fresh install than _google_…
Manifest v3 will probably be the straw that forces me to switch back again, but reluctantly.