You're right, there's a big difference.
Though I'm not convinced the blatant copying you mention is that all-encompassing and mainstream, some of the specific pieces you mentioned seemed more inspired by rather than copied (samurai jack for instance), but maybe I'm wrong.
Just to clarify, I'm not defending Hollywood, I just like try to add more perspectives to the table: so what if we have copied movies? If we are not aware of the original, in our perspective we are seeing something new?
If people weren't seeing them as new they wouldn't watch and such movies wouldn't bring money and Hollywood wouldn't shoot them. So it's not a waste, as long as it's a copy of a good movie
The important thing at the end of the day, if you enjoyed a copy-movie, is not to idealize people behind it, but that should be the case with anything,people are never perfect, geniuses that are wonderful human beings etc, there's always some uncanny detail lying somewhere.
I liked Samurai Jack, I don't necessarily think it's the most brillitant piece made by unbelievably creative and original people