Could be a plethora of different reasons...I have an MBA and wasn't selected. From what I've gathered here, I'm thinking it's my civilian experience.
Work experience is 120% necessary. Not just years experience, but it has to be directly relevant to the designator (or what they're looking for with regards to the designator). Motivational statement/interviews also make a big difference. Go volunteer in some org, whether it's an employee network or volunteer community service, etc. I like to spend a couple hours a week with my local Surfrider Foundation chapter when I'm free Saturday mornings, and they don't limit slots like Habitat for Humanity or the Food Bank do so it's great. It's really easy so if you have something like that in your city, take advantage of it.
For what it's worth, this chart I have from my local recruitment office for "Reserves DCO Competitive Profiles" lists "DoD Contracting experience a big plugs/DAWIA certs" as a positive factor. "Competitive" GPA is placed at 3.34.
I can only theorize here, but university name recognition never hurts.