Probably best to leave those who can't read by 4 or 5 to go on to the public schools since they really aren't all that intelligent when you get right down to it.(/sarc but in some cases true).
It’s true that some people aren’t as intelligent as others. However, if the goal is to assist people in developing their abilities, such as they are, to the fullest, our public school system wouldn’t be the means I would recommend.