****If she were a ravishing looking woman with a certain "it" factor on screen who was in her 30s or early 40s, I'd very much buy that.***
But that's not what it says in the script, and presumably not what Glenn was playing the first time she did the role. (Though, honestly, one of my problems with her performance the first time was that I felt she sometimes did come across as an old crone.)
Yes, you can rewrite the property to make it about a former actress now in her 60s or 70s, but that's not what the original is about. In the original, she's not even "in her 50s," she is just 50.