Dear Curt,
Sorry, you're right, that wasn't logical. What I meant was 'if people buy it, they will continue to make it' -- of existing products, obviously. Thus Ilford dropped 220 (and 70mm) because they weren't selling enough of it. Pan F (any format) has been marginal for years.
Super-XX was killed because it was the last cadmium-containing film in the Kodak inventory, not because of poor sales, but Azo (as I understand it) was an economic decision: they just weren't selling enough. The man who was responsible for signing the order killing Super-XX requested that no-one publish his name because he was afraid of death threats.
But Ektachrome 64, a truly awful film, remains in production because people insist on buying it. There are (or were last time I checked) some at Kodak who are embarrassed to be associated with such a terrible film.
Cheers,
Roger