From these graphs by Cato, it certainly hasn’t been the kids….
With all of the massive spending (taking from all levels of educational spending, it is now larger than military spending – in the middle of two wars):

And why, please tell me why, costs are up almost 100% since 1970 when enrollment are up, perhaps, 10%)?
And no, I do not accept what one of the leaders of my local NEA union said during my hamlet’s Deliberative Session (where all the town folk get to discuss the annual budget just before we all vote on it) when a cut back in spending was requested: "the number of kids is down but the needs always go up" (she was not more than 5 feet away from me when she said it, semi-under her breath, and a horrified look on her face appeared when she realized that I had heard her – I’m on the Budget Committee).
Considering that it is the Educational Establishment that always seem to be the one that determine when the needs are going up….
(H/T: Powerline)