Even though his cult was on the rise, I think Hitchcock's talent was in steep decline through the 60s.
His attempt to turn Tippi Hedren into the new Grace Kelly was always doomed - she lacked Kelly's spark. Mind you this was a tough role, and picture, for any female lead to shine in. The movie was flat and dull; and Hitch laid on the cod psychoanalysis with a trowel.
Plus the awful rape scene in which Hitch seems to have unleashed his own Id all over the set. The only thing worse was a scene in Frenzy with a close up of a girl being strangled to death. The Hayes Code was Hitchcock's best friend.