One reason, as I posted somewhere else, was that he was injured last summer, and played very litle AAU ball. He played on the Boo Williams AAU program, which is one of the best in the country and is loaded with D1 talent. So even when he played, he likely didn't get much exposure.
Then, a couple other reasons might have been--
Because of his injury, he got off to a slow start during his HS season. He had another, higher-rated player on his team that got most of the attention, and he played in Richmond, which is a hotbed for high-quality basketball talent, so I think it's a little easier to get lost among the other great players in that area.
He was a late bloomer, who bulked up and grew a lot between his junior and senior seasons. I found one site that listed him at 6'2", 170 just a little over a year ago. And he lead his team in rebounding as a junior, so I wonder if he didn't play more of a forward position, and had less chance to handle the ball and shoot.
Here is a preview article from Dec., 2008, that lists Jake as a 6'3" forward--
http://74.125.95.132/search?q=cache:ggYDIdopCKAJ:www.timesdispatch.com/rtd/sports/high_school_prep/high_school_basketball/article/BCAP2_20081201-212259/126131/+%22Jake+eastman&cd=11&hl=en&ct=clnk&gl=us
We all know it happens, and recruiting is a crapshoot. Josh Young of Drake got very little D1 recruiting interest, as did some other great shooters we have seen in recent years in the MVC like Blake Ahearn, Kyle Korver, Kent Williams, Ben Jacobsen, Marico Stinson, and Jeremy Crouch