Of course, they were adaptations to begin with, but still.

There's a fascinating article at The AV Club about an important fact that may be fueling Disney's current passion for live-action remakes of their classic animated films: Disney owns the scripts for those movies wholesale, so they can remake the films without paying the original writers twice. There's nothing actually illegal about this (the original scriptwriters presumably knew what they were doing, contract-wise), but it makes Disney look pretty tightfisted.