The thing about being a model is that your world revolves around what people think of you in the shallowest way. That's the nature of your life - first impressions are the entire thing that exists professionally. So every little thing is amplified. Someone doesn't like you - it's a threat. You have a bad hair day - it's a disaster. Etc.
Plenty of gorgeous ladies who have no interest in being "models" and those are the ones to look for.
First line nailed it...
It's ironic because a lot of these models are so deeply insecure.