The Jungle Book - 1967
Little Mermaid - 1989
Beauty and the Beast - 1991
Aladdin - 1992
Lion King - 1994
It's likely more a question of what you grew up with. When I was a kid I remember heavily disliking many of the earliest Disney animated movies like Pinocchio/Dumbo/Bambi but I absolutely adored the animated Robin Hood, Sword in the Stone, etc.
Rest of the films you mentioned - The Disney Renaissance the parent parent’s comment mentioned - starting with The Little Mermaid in 1989, and it seems generally accepted this lasted for 10 years?
https://en.m.wikipedia.org/wiki/The_Jungle_Book_(1967_film)#...
The Lion King is pretty much a flawless film. And that came out 28 years after Walt Disney died.
No need to wonder: there has been, and basically all Disney 2D animation, even what little they do for the cinema, is outsourced overseas.
Basically, reverse engineering that process is probably a more expensive undertaking than most studios are willing to take. Look also at the Cuphead animated series, which was animated like a modern production (sadly).
[producer and director] had written the role of the Genie for Robin Williams, but when met with resistance, created a reel of a Williams's stand-up animation of the Genie.
The directors asked Eric Goldberg, the Genie's supervising animator, to animate the character over one of Williams's old stand-up comedy routines to pitch the idea to the actor. The resulting test, in which Williams's stand-up about schizophrenia was translated to the Genie growing another head to argue with himself, made Williams "laugh his ass off", and convinced him to sign for the role.
Williams's appearance in Aladdin marked the beginning of a transition in animation to use celebrity voice actors rather than specifically trained voice actors