I'd like to start giving people the option of commenting on shorter Cold Takes pieces (which I don't cross-post here or provide audio for). I'm going to use this post for that: I will generally leave a comment for each piece, and people can leave their comments as replies to that.
An interesting counterexample to some of your points is the Disney Renaissance, generally considered to be the golden age of Disney animation, which started fifty years after Disney began animating films. AIUI, the conventional wisdom is that there happened to be a confluence of incredible talents: in particular, Howard Ashman and Alan Menken were an incredible songwriting duo. The Renaissance was also when the iconic Disney princess line was invented. Before the Renaissance, Disney happened to have made films about princesses, but it wasn't a distinct category, any more than films about talking animals were considered a distinct category. The anecdote I've heard is that a producer noticed that girls were wearing handmade Sleeping Beauty and Cinderella dresses, and decided to appeal to the obvious market here!
I for one would be very interested in it if you decided to look into why the Disney Renaissance was so good so long after Disney began animating films.