I post this video not to disparage Disney. Truly, anyone who's ever tried to animate realistic movements of a basic skeleton knows how hard it it is to get it right. So I don't blame Disney for developing one that's really excellent and then using it repeatedly. I also don't find it surprising that the skeletons reused are mostly for dancing. Early animated dancing was either poor, or it was rotoscoped from a live dancer. Hell, when animators didn't use rotoscoping, it was a big deal. Tex Avery's Red Hot Riding Hood's first dance sequence was so well done, everyone assumed that it was a real person being traced, even though it was all free-hand.