That makes a lot of sense though. I mean, in America, if you want to model, you get to an agency. Agencies are relatively local. I mean, worst case you have to move a few states over. The girls that audition for ANTM are really either girls who have been rejected, want fame "fast" or don't know enough about the industry to know its better to walk into an agency.
In places like Vietnam, the only way to legitimately become a model is to get noticed on a place like national television. Or so I assume. I can't imagine local agencies having strong ties to American and European power agencies. So, getting on a show like VNTM may get you noticed faster in the west and so more legitimate models compete.