I think you oversimplify things. That manufacturers were after their profit no one doubts. Most likely you are after such too. But international price discrepancies in general, including all consumer goods, were more complex than that. So there were import taxation trasholds, but also internal extra taxation on certain goods that affected retail price. But also the standard of living grossly differed. This made manufacturers calculate a lower profit at some and a higher profit at other markets for their ex-factory prices. in order to sell. Moreover there were even important markets were manufacturers installed prescribed retail prices. This was part of consolidating their market position, but also offered the consumer being located in a big city or a remote village to buy consumables (e.g. films) and and even have a decent offer of higher value goods (e.g. cameras). Actually such system nourished the existance of thousands of photo retailers.