I would argue that a lot of Disney's woes happened because of the combination of Michael Eisner and Jeffrey kastenburg ironically enough.
Katzenberg was basically a slave master that worked animators to the bone and almost caused now renowned films to tank because he wanted to omit some of their most iconic parts ( he tried to remove songs from the original Little mermaid which pissed off Howard Ashman).
Eisner on the other hand made a bunch of pointless investments that eventually cause the company to fall into hard times what's really strong when the animated film stop being as successful as they initially were post Lion King.
Bob iger was sort of seen as a savior years ago because he minted the poor relationship between Disney and pixar, I bought them, and then went on to purchase other things like marvel and Star wars but we now see how his reign has turned out in the long run
The problem with Disney is that it's hard to pinpoint where they exactly was wrong because they do good for a minute but then drop the ball hard