I think, disregarding and personal choices she have made to scale back, if I were to hypothesize as to why she has faded - I think she, along with a few other girls like Kris Grikaite and Birgit Kos (who all debuted around the same time with the same Prada cut) are simply too beautiful for what the industry is looking for right now.
And especially for her and Birgit - they're so womanly, so athletic and thoroughbred looking. The kind of beauty that these three girls have is intimidating and fashion now can't handle that. If it were 2003, they'd be up there at the top with the rest of the girls we know and love from that era. But, now, the industry wants gangly, inoffensive, very young and forgettable looking girls.