One of the issues with ANTM winners is that by the time they have won as a finalist on the show, their “image” is burnt out. There could be issues with something they have said or done which may end up affecting the marketing goal. There can be negative affects as well if she wasn’t considered the most popular by the viewers opinion and that leads us to the last fact. The actual viewers of ANTM do not account to a large enough percentage to have much of an effect on the actual fashion industry. So besides the campaigns and contracts that were promised by the actual competition, none of the ANTP contestants have done anything to “TOP” their careers as models.

Source: Have any of the winners of America’s Next Top Model become top models? – Quora