This, ladies and gentlemen, is the dark side of the whole "copyrights" thing.

On the one hand, it's there to prevent people from making tons of money at the expense of people who actually put significant work into a given product.

On the other hand, to protect rich companies already wallowing in profit from... having a small portion of yet more profit taken by people who actually put the work in.

I understand, at first it's like "we need those costumes designed, but you see how we're spending lots of money on this project (incl. paying you) and do a lot of coordination work etc., and we're not getting the money back, or profit, without selling these merchandising products, too... sorry" - but after 40 years have passed and the company already got nigga-rich, not least due to the... merchandising?
"Nah, we're not gonna let this guy have a piece now, we need someone... to protect our rights!!!"

The dark side, people... the Dark Side.