You need very cheap labour as the flowers must be collected within a matter of hours by hand, then rapidly sorted to avoid the stigmas rotting, etc. Spain produced the most famous saffron in the world but this is almos a memory as the problem of gathering a number of people together for the harvest is difficult. It was possible when large families lived in the country in the past so friends and neighbours could help along but now the young try to migrate to cities, etc. It is as Shirley says, there are less sources every year.