I think the group didn't initially give schools priority buy was because there was virtually nothing out there. It's fine if you want to push a new product onto schools but most schools don't have a budget for any sort of internal support much less any sort of external support contracts. I think the group was trying to bulk up the community (ala Arduino) so the teachers and students have someone to turn to.
Which kind of leads me to my next point. I can't vouch for the rest of the world, but schools up to the High School level state side are practically being spoon fed the curriculum. It's kind of embarrassing really but I digress, Pi isn't going to be a part of any school, at all, if it doesn't make it into the curriculum (or that whole Obama

gets

). I would imagine that the group was hoping to get enough market penetration that more schools might take notice. I dunno, I'm just guessing.
That whole ---That which is odiferous and causeth plants to grow--- with the NDA and the ---fouled up beyond all recognition--- up boot sequence might have something to do with it. That would be a stretch, but if a product markets itself as a student worthy product where they can get into the nuts and bolts but proceeds to hide some of it away, I would look elsewhere.
But yeah, a shell is necessary, at least a clear one. In college, we beat the ---steaming pile of meadow muffin--- out of the 68HC11 boards just by moving them around. I think the hardware class spent half their time soldering those poor boards back together so the software class can hammer away at them.