The one area in which Hollywood discriminates that is uncontestable is age. Films are special projects, and they have little value when a major star or director bites the dust in the middle of production. Lots of insurance is written to protect investments in production in case the worst happens. He may have had health issues that made him uninsurable, or perhaps he couldn’t pony up a share like Clint Eastwood, who was able to make movies into his 90s. Dunno. I recall learning about this phenomenon when David Lean directed a film anonymously in his later years because of uninsurability. Hollywood is first a financial business, then an artistic one. Some of that discrimination makes perfect sense.
What film did David lean direct anonymously? Was this after his film “A Passage to India”?