If you don't make copyright contagious under derivative works then people can just change a few things to get around copyright.

Also, do you really want a world where big film studios can just adapt books of writers without compensating them?

Is 20-30 authors per year making it big really worth the massive suffocation that prevents tens of thousands of authors from writing the stories that are in their hearts?

They do that anyway today. You really think authors, book writing being the lucrative industry for writers that it is, are suing Universal/Sony/whoever to prevent their IP being infringed?

I do really want a world however where fans/communities can riff on and make derivative works of culturally relevant material without being legally nuked from orbit. The last few weeks have been amazing in the gaming world, creativity abounds and there seem to be no limits as to what we can redesign to our own whims.