Well, so there is guaranteed access to free study materials. It doesn't mean that pay-as-you-go study materials won't also be available. I'm having a hard time finding a huge problem with there being free materials availble to everyone, and alternative materials available on the market. If the free materials suck, that is a problem, in that the population that can only afford the free materials is *still* at a disadvantage. But given Kahn's record, I don't see that happening. My daughter just went through SAT's this year, and used two different study guides because the material is presented differently and she connected better with one than the other.
What disadvantaged kids are more in need of is someone to tell them how important the SAT is, and to get them pointed at *any* study materials at all, and encourage them to use it. The conversations that I hear among helicopter parents here in the suburbs where I live now (people pay up to live where I do because of the schools) are light-years removed from the conversations I overheard as a kid, where for a good 1/4-1/3 of my contemporaries, their highest ambition in life was to have a dairy farm that milked more cows than their dad's farm did. My parents, fortunately, emphasized education. But for kids that don't come from that culture, they need to be, quite literally, led to and shown the study materials and benefits thereof.