The 1958 film Vertigo was directed by Alfred Hitchcock and starred Jimmy Stewart. Here and there I encounter the suggestion that upon the release of Vertigo, Hitchcock felt disappointed in Stewart and decided not to work with him any more.
For example, at the Wikipedia page on Stewart:
The director reportedly blamed the film's failure on Stewart looking too old to be Kim Novak's love interest, and cast Cary Grant as Roger Thornhill in North by Northwest (1959), a role Stewart had very much wanted.
At the Turner Classic Movies page on Vertigo:
For the cast, Hitchcock wanted James Stewart as the detective from the beginning of the project. Vertigo would be the fourth Stewart film directed by Hitchcock; it would also be the last. Hitchcock would later complain that Stewart, at 49, may have been too old for the role...
What's the source of this belief? Was it only suggested long after the 1958 release of Vertigo, when the idea of a Hitchcock-Stewart collaboration was implausible on other grounds? Who reports that Hitchcock "blamed" or "would later complain" along these lines, and when did he report it?