Maybe this is too obvious to be a "theory" but my main observation about Disney movies now that I have a 2 year old and am rewatching/watching-the-newer-ones-for-the-first-time is that their staying power and quality is purely a function of how many bangers are on the soundtrack and nothing else.
"Frozen" is embarrassingly stacked. I think only "Aladdin" comes close. So much was written about why Disney animation entered a late90's / early 2000s doldrums and the answer ("hey let's have Phil Collins write our songs on this one") couldn't be more obvious.
Both Pixar and "The Emperor's New Groove"'s success really pointed them in the wrong direction towards embracing more adult storytelling and sophisticated themes when "Frozen" finally got them back to basics: writing a bunch of catchy showtunes sung by big Broadway voices.
@mtsw there has been a lot written on this, but the Treasure Planet and Atlantis dead ends were almost entirely driven by the desire to get into the teen boy toy market that Disney ends up just buying with the Star Wars and Marvel purchases
@stoke123 @mtsw I really liked Atlantis as a kid (though still would have been better with songs)
@space_wizard I personally think both those movies are very good. It's just they were aimed at teen kids from a very uncool company.