I was hired for my current individual contributor job at age 65. I guess the cutoff must be 70 now. Of course it helps that I do have three somewhat esoteric skills that were needed by the company that hired me, but it's nothing a relatively good programmer couldn't pick up in a reasonable amount of time.
Let's just say that commonplace skills don't cut it the older you get. Someone who knows ONLY Python and SQL will be out of a job by age 40. Being expert at C++ might keep you in the game until age 50. You might be employable to age 60 if you know OCaml or Haskell.
In the end it's all supply and demand. If your skills are a dime a dozen that's what you'll be paid. And you'll be replaced by a younger, cheaper person as soon as they can find one.