I think Beauty and the Beast and the Lion King hold up just fine. Both films are relatively timeless in my book.
I think if you showed them to a young audience today, yes they would be timeless, absolutely. I just found that they didn't grow up with me. We are puzzle pieces that don't fit anymore if that makes sense, lol. If they still fit other people, that's great. Again, the music is still wonderful, if anything I appreciate that even more now than I did then.
I very much enjoy Classics like Snow White too, but they certainly aren't any more timeless than the modern classics. Snow White is a very much the model for a demure young woman in the 1930's. For some reason, this means less to you than an Ariel or Belle representing the young women the 90's.
See, hmm, thing is I don't mind the way women were portrayed in early Disney films. I don't see them as weak or passive. The whole point of Snow White, Cinderella and even Sword in the Stone and Pinnochio is that these are characters that are abused and bullied by society. And yet they remain good, kind people. They never lose hope that things can get better. That is something I can identify with in my own life and what most people can identify with.
The heroes of the '90s films just come across like upper middle class kids who are bored with suburban life and yearn for more. Ariel and Jasmine are princesses and Simba is a prince, I can't identify with them or feel sorry for them. Belle, yeah they think she's weird, but all the men in the movie think she's gorgeous. Again, no sympathy, lol. Like Nostalgia Critic once said, characters like this can come off like spoiled brats. The only modern Disney heroine that I can still relate to is Mulan because she truly was dealing with a difficult existence, being a woman and living in oppression.
I think it's really a sign of how society changed. Like was harder for the general public in the 30's and 40's (and people remembered this in the '50s), they needed hope to get through life and the dream that things could get better. In the late '80s and '90s, more yuppie, "30-something" problems came into vogue and that comes across as petty by comparison. Plus they were trying so hard to make the women liberated that it often seemed forced. That's why the Animaniacs started making fun of Disney and "just the same old heroine."