Will you reach a limit if you come up with a telescope ten times as big - where is the real limit? Is that an exciting question? I think there is a bit of rhetorics involved at interpeting the result of this experiment.
You can also use Earth's atmosphere as a lens too! It's an amazing video: https://www.youtube.com/watch?v=jgOTZe07eHA
Going even crazier, I can imagine we could some day use a massive black hole as a giant telescope.