Bella and Jill are worse, yes. But talking about tall, skinny girls with big boobies, three words: breast augmentation surgery. Look at that girl that other user has posted a few comments over this one. She really looks like Sage, and her tits are as fake as Judas.
Breast are mostly body fat. If a girl doesn´t have body fat, she will not have breast. As simple as that. Sadly for women, body fat goes first to hips, belly and butt, not breasts. Even if she was fat when teenager and developed big breast, and then lost a lot of weigh, she would not keep the same breast. Generally they would deflate and become shaggy.
Anyway, problem in Sage are not breasts. They are perfect. Problem is waists. She looks anorexic. In real life, in a body like that, we could see the ribs protruding.