Nobody rattled my cage.
Just pointing out that it's obvious - from a purely artistic/critical perspective (which is what is being discussed) - she could have chosen far more worthy/challenging roles if she'd wanted to. I don't doubt plenty would have been offered to her.
So in that sense, it's actually quite reasonable to say she hasn't delivered on her potential. All depends how you look at it.
Failure to deliver implies obligation. For there to be a failure to deliver there must also have been an obligation to deliver in the first place. The OP seems to be under the impression she is under some sort of obligation to chose worthy/challenging roles and win awards. Is she?