It's also true that (IMO) we're trying to get everyone to meet a benchmark that a fair number of those people probably CANNOT meet. The reasons are myriad, of course-- but some of those problems are mutable and some of them aren't. Until we start (as a society) teasing apart which problems can be fixed in that cohort, it seems an awful lot like throwing good money after bad.
Well, we actually need to start before K. This is why Obama is pushing pre-K, to the dismay of the right and the left and so on and so forth. The research is fairly strong, but it has to be really, really good pre-K, not cookie-cutter, with trained teachers teaching a complex curriculum with care, sensitivity, and community support, and unfortunately that probably doesn't scale at all well. Still, states like OK and FL that have instituted universal pre-K have seen some gains.
There's interesting work being done with interventions to get parents to just TALK to their babies more. They use a device to measure words spoken. You get feedback quickly so you try harder. People really do want their kids to succeed. Many don't really know what this would entail.
