No Iger fired Dick Cook because he still wanted to make smaller movies and adult oriented movies, not just tentpole city. Iger elevated the then head of the Disney Channel, Rich Ross, to run studios as his guy. Lasseter and others hated how he ran the studio, he worked in TV all his career and had no experience with film or feature animation. Lasseter’s contract was coming up for renewal in ‘13 and he demanded Ross’ ouster after “John Carter” and other things. Alan Horn, who was basically kicked out of Warners for being old despite doing an amazing job there for ten plus years, was a free agent and Lasseter brought him to Disney to take over the studio.
That’s a very condensed version of the history, but you get the point.