It was just less of everything than Chrome. First install experience for an average user was much better in terms of speed and snappiness. That was one of the keys to its success.
This is insane. As a power FF user, I don't think Chrome ever "got ahead". There were 2 reasons for its success (in order):
1. Made by a respected company that was killing everything in those days.
2. It was occasionally faster, and more stable.
Feature-wise - it was always worse.
Chrome was simply touted as an insanely fast browser. At the time, Firefox was an absolute dog when it came to performance and heaviness.
That was enough to win - Chrome kneecapped Firefox over that metric alone.
For me, the speed improvement in Chrome was marginal. Perhaps my PC at the time was simply too slow to notice the difference.
The thing is - I was happy to sacrifice speed to get the features in the addons.
And before that it was Netscape
All of this has happened before, and all of this will happen again.
That is ahead for the majority of people.