For what my two cents are worth, I think the reason this program would not benefit those who cannot read, is because you have to be able to understand the written language before you can benefit from PRing. I'm still in my infancy here in the PR world, but I think I've learned enough to understand that you have to be able to read in the traditional manner before your mind will be able to make the transition to reading at light speed.
An apt example would be if I were to try to PR a Russian text, in cyrillics, or try to get something out of Arabic. I couldn't even pronounce a word in cyrillics, even though I understand much of what is said verbally, based on my waivering fluency in Czech, because many of the words have similar root phonemes that are attached to similar meanings. Nevertheless, you might as well give me something to read in Sanskrit as Cyrillic, because it's all Greek to me.
I hope I'm making sense. I agree that PR should be a part of the curriculum taught in our schools, but it would probably be best suited for capable readers say 5th grade and up, or something like that. Unfortunately, this may be the equivalent to a really effective surgical technique, but it is no cure for cancer.
Bill