I don't think it's a very good point Gillen brings up or at least it's not a well thought out one, if you look at characters and stories in other mediums there are characters and concepts that people refer to the originator here's a list.

Movies- Die Hard plot, Ghostbusters,
Anime- Gundam, Fist of the North Star
etc, etc

Hell even comics has it's own derivative characters who are popular, Daredevil would not exist without Spider-man or Spawn with Venom, Saga has been noted to very Star wars but is very unique on it's own. It was a interesting thought until you think about it and he could apply it to more mediums than just comics, whatever becomes the Paragon is often just people gravitating towards a version they like.

To be fair I think some things are weighed down more than others. I remember an anime called Andonah Zero which tried to compete against Gundam and while it was popular for a while it's not talked about in good regard. I just think Gillen thought of it only applying to comics is not true. Spider-man has a lot of Clark Kent in him early on but you rarely hear that he is a complete rip-off of him or burdened by that connection. I think a better argument is that with comics you can trace inspiration very easily since it's a young medium and there have been a lot of writings on it.