I don't think you'll ever get the film and TV industry to campaign for a reduction of copyright authority, even if it benefits them in that particular instance.
Just propose a retro-active extension of copyright so that all the Disney movies based on fairy tales (which aren't actually _that_ old, at least the versions they based their movies on) require licensing of the original story.
That probably produces quite an outcry (given how hard it likely is to identify all constituents of the estate).
