How is this any different than say GPL in that you can either pay the price "make your modified version GPL too" or you can not modify the software. Do you also think that's not for them to decide and that you should just use and modify the software anyway?
PS: please don't turn this into a thread about the minutia of the GPL. That's not the point. The point is whether or not the same concept that lets a creator set a software license and choose the terms, whether that concept also applies to other creations, videos, books, movies, games, magazines, articles, etc..