> Part of what made chrome succeed is it came out with a pretty robust set of webdev tools right from the get-go.

I think this factor isn't given enough weight in the shift to Firefox.

At that time, the largest pain point in web development was (by a long shot) browser compatibility.

When developers fell in love with Firefox, they started pushing business requirements away from IE and towards the browser that didn't feel like it was their enemy. Alongside with this there was also massive shift to start taking web standards seriously, which is another area where IE dropped the ball spectacularly

It took a few years, but eventually pointy haired managers got sick of our whining and gave in.