This is very well known. Disney old movies reused a ton of assets whenever possible, it wasnt a matter of the artists wanting to make the job easier, it was a matter of reusing assets that had already been built. Several of those were rotoscoped and thus it was easier to reuse the rotoscopy already used previously than getting funds to do it again. These rotoscoped dances and etc were gotten by the studio to be used in the way they were used.
This is not, artisticaly, the same as what Greg Land does, which is an artistical nightmare, Greg Land literally steals work from other artists repeatedly and traces both from photographs of actors and several other works of art. You can go through his pages and find the stock poses again and again. Compare it to Alex Ross, who also works based on photographs he takes of models but prepares them himself and you can see a brutal difference.
