Really? If people are saying that pre-school doesn't teach anything, then it probably depends on the school/teacher. I know of many online preschools and I have seen proof personally that, it depends on the school/teacher. My neighbours, put their daughter in online preschool, by the end of the year, she could do as much as a 1st grader! Again I think it just depends on the school or teacher.
Pre-school does not even teach anything, it is more like a baby care for parents who have other students at a school near by or who need to get to work. I think it is more important to have the kids at home longer with their parents because sometimes parents teach a kid way more.
Standardized school curricula have shown to be restrictive to child learning and development. As the diversity of our population grows we need to maintain an open mind to the individuality of each and every student. Imposing a set standard is definitely not the way to go about achieving our goal.