To help highlight where there are changes and where there is continuity at the top level, here's a table of who was the MoCo CEO, MoCo and MoFo Board Chairs, MoFO President, and MoFo ED over time for the last ten years.
Ousted doesn't equate to making some changes then walking away in my mind. It doesn't sound like she was in-amicably forced out over results or the like.
I remember her expanding the number of positions on the board (and the often discussed compensation) not too long (relatively) before they had some rounds of firings. I remember being confused why one or both of the ones that joined said board(it's been a while) seemed...completely unrelated to both Mozilla or it's field of expertise or so.