Google launched Chrome in 2008, but up until 2011 was not a threat to Firefox. Chrome eroded Firefox slowly and around 2011 really hit it off. Mozilla stood still while Chrome evolved, and at the point Chrome extensions were covering 99% of what Firefox was offering, started losing market share in a big way. Now Chrome sits at around 50% market share, while Firefox fell under 10%.
Now, today, Firefox is still not fixed. Memory hog, frequent freezes, flash plugin crashes. What does Mozilla do?
You now what? Let’s ask users to sign in! Let’s make the options more complicated!
They go out their way to not fix the most obvious problems, but make the browser harder to use.