In another thread I did mention to Juan, the OP, that I've seen photochemistry in stores in Chile, in Santiago and Valparaiso some of it packaged for them locally.
I think the issue is low or lack of demand for more specialist chemistry making it uneconomic to ship and distribute. I noticed that Kodak had little prescence in the B&W market , Ilford and Foma dominated, and there was very little Fuji B$=&W film. Minilabs on the other hand were all Kodak and Fuji and plenty of colour film.
Ian