I used to deal with Calumet quite a bit. They even had a sizable outlet in SF. But once they pretty much abandoned anything "analog" or darkroom gear (and they had a niche on quite a bit of that, including Zone VI, various temp valves, some nice mic you couldn't find anywhere else) - at that point I lost interest in them. Even the camera store right down the street had a way better selection of film than they did, even sheet film. They still sold certain studio supplies like backdrops and lighting, but not competitively. As a business model, putting all their eggs
in one basket probably wasn't the smartest idea. It amounts to lack of "genetic diversity" product-wise. Maybe they had internal problems too.