In USA, preschool is not considered to be as important.
Explanation:
In USA, only 69 percent of all children go to pre school and are instead kept at home. Most parents usually see preschool as unnecessary or sometimes a crutch to keep children in if both parents are at work and unable to take care of the child in the time.
The preschool is lot more serious matter in Asian communities as education from an early age is prioritized in those cultures which is not as much the case in the USA.
