There's no basis for a lawsuit, but that doesn't mean someone won't file one anyway. You can't claim a copyright a general plot concept like "someone goes into dreams and steals ideas."
Big deal, people have been passing down and modifying stories for generations. It's almost impossible to come up with a
completely new narrative; every story is influenced by something that came before. If Nolan "stole" this idea, at least he didn't steal an idea for a mismatched pair of cops or a mismatched pair of lovers or some other concept we've seen done a million times before.
Good point. What's the saying? There's nothing new under the sun. One of the rare instances you'll catch me quoting from the Bible.
There really is virtually no originality possible. Ideas can be refreshing, seldom used, have a fresh twist, be given a jump start, but original? I doubt it. However, I thought Inception came closer than most.