Concerning Natalia and other models who look "plain" in real life; what a country deems as a plain looking girl, fashion can deem as unique beauty.
In Brazil, Gisele is celebrated because she is Gisele, but many Brazilians don't think she's the most beautiful or sexy girl out there; but to the fashion industry she is deemed as the standard of all supermodels.
In China, Liu Wen is celebrated because she is Liu Wen the first Chinese model to walk for VS, but the general public don't look up to her as their standard of beauty because she looks like a regular Chinese girl; but to the fashion industry she is deemed as exotic and unique looking.
I mean, remember how so many models were called ugly when they were younger? It's because to common people, these models weren't the most attractive, but when you stamp "supermodel" on their faces, they then become the most beautiful.
Fashion is and will always be the polar opposite thinking of what reality is.