If you say the original crew did not do all the labor required to make the franchise grow in the future (obviously true), you are now arguing different people have had incremental impact on creating the wealth, which is kind of the point.
Are you saying that he/the small group are solely responsible for Disney wanting to pay 4 billion for it?
The Star Wars franchise earned a tremendous amount of money before the one-time Disney payout.
Jk Rowling and LeBron James are additional examples.