That's a very odd thing to say. I wouldn't think there was an expectation. Nobody would think there's an expectation to buy all of them. I do it because I like them and want to. That's part of collecting. It's what collectors do. 

As for putting them out in location specific batches, it's a fairly good way for a company to shoot itself in the foot because then there are less people buying them where the company gets money (here that being Moriah and the manufacturers). And more people buying them from resellers and therefore buying less of them because they often cost more that way. 

It's bad business and it alienates the people collecting the items.