The ISS

Id say there are an equal (or greater) number of companies in ceramics,
chemicals, steel and other materials processing, pharmaceuticals, energy
production, entertainment. A problem with any kind of materials processing is that for any advantage which one might cite for 0-G (or whatever), someone can come up with an alternative here on Earth which, even if not quite as good, is a great deal less expensive. In my younger years, I read G. Harry Stine, and was tremendously enthused about materials processing in space. I remember extolling to a college physics professor the virtues of foamed steel. And he said, "What about honeycomb composites?" I was crestfallen. Even O'Neill, who was hardly one who could be accused of overlooking an advantage of doing things in space, was not very optimistic about 0-G materials processing. That's why he concentrated more on energy. A comment has been made that the problem with all the people (both inside and outside of NASA) who have in the past tried to sell space based on materials processing is that they are often not materials processing experts. They are space experts. Thus they are more attuned to a space solution to certain problems than a possible Earth-bound solution which might work nearly as well.