Hm, also at 10 years out how likely is the author to be able to convince someone to do a TV adaptation, knowing that by the time they're done someone else will be able to release their own versions (sans royalty even)?
What about Shakespeare.
What about the Brothers Grimm. Should Disnay have to pay for those fairy tales?
In the end every creative work stands on the shoulders of giants. We should reward creators for contributing to our culture but this notion that they should be able to own their creations way past when they become popular is absurd.