To quote: "Developers. Developers. Developers. Developers. Developers."

I personally think Chrome gained so much market share, in large part, because it simply had the best developer tools.

Firefox had FireBug, which was great, and revolutionary for its time!

However! Having FireBug meant that Mozilla's built in tools never got much attention. So their dev tools were severely lacking, and stagnant. They remained that way until a few years back.

Meanwhile Chrome's dev tools just kept advancing. So in the end, FireBug (unintentionally) helped FireFox lose major marketshare