A lot of them are going down the mommy blogger route which is also pretty lucrative if you strike while it's hot. See Romee, Elsa, etc.
It's sad but many models start in their mid to late teens and by the time they're in their mid to late 20s, they're not working nearly as much as before and the fashion world has moved on. We had heroin chic, skinny Eastern Euro look, Brazilian Amazons, Dollface models, and androgynous models all within the span of a decade or so. They might as well focus on other things in life.