The issue is, what happens if you have a work where e.g. the music and the script were written by different people? If one of them can terminate the license then you create a situation where nobody can distribute it because nobody has the rights to all of it anymore.
Of course, what they should do is have the copyright expire after 35 years. Then if the original creators want to make sequel at that point they're entitled to -- just like everybody else.
> what happens if you have a work where e.g. the music and the script were written by different people?
This happens ALL THE TIME. 2001 A Space Odyssey, Heavy Metal (1981-Blue Oyster Cult), Rocky (1976) airing on TV without Eye of the Tiger, It's a Wonderful Life was public domain but distributors needed to pay for the soundtrack. TV shows like Married with Children and Dave airing in syndication with different opening theme songs. etc.
All over archive.org you'll find tons of classic films but with the soundtracks stripped out.
Of course, what they should do is have the copyright expire after 35 years. Then if the original creators want to make sequel at that point they're entitled to -- just like everybody else.