The current superhero renaissance in cinemas around the world could also be construed by some as a constant glut of more of the same. They would be wrong of course, but they are still entitled to their opinion.
For their part, most of the cast agree with the sentiment that there are way more stories to tell. For context, here is the exact question.
abbottom asked "Do you feel there's a limit to the amount of possible plots for superhero movies? Have we reached the limit, or are there many more original and engaging stories to tell?"
For Chadwick Boseman, that is an emphatic no.
"Absolutley not! As long as your story is character based, there is an infinite number of possibilities."
Robert Downey Jr. agrees, even teasing Infinity War.
"Joe Russo was just pitching me some of the Infinity War stuff, so you'd better hold on to your hats. Sky's the limit."
As for Director Anthony Russo, he cites the variety of story types that have already been used in Marvel's cinematic universe as proof that you can expand the genre in exciting new ways.
"The beauty of superhero movies is that there are always more stories to tell. You can go anywhere with the genre. With Winter Soldier we mashed up genres by making a political thriller. With Civil War we are doing a psychological thriller. Infinity War will be something else entirely. And other filmmakers are finding new ground all the time. You can go epic, or you can do small and intimate character work. You can do real world or fantasy world. I think we can all look forward to many more years of surprising and original superhero movies."
You also have to remember that these films come out every year, but in between the films these characters are being used in a myriad of ways in the comics and on TV, which just provide more and more reference material for future films. They all feed each other, and as long as they keep building strong characters, I don't see it ending anytime soon.