It is true that young children need to eat frequently. They often get hungry during the course of a morning's worth of active play. The answer, of course, is that we do not know precisely when each person in the classroom will be ready for snack, or how much each will want to eat.
Some children eat very large breakfasts and are hungry in the late morning, if at all.
Others are too busy playing or sleeping late at home to eat much of anything before school. They may be ready for snack soon after they come in the door. Some children digest their food very quickly and are as hungry as bears whenever snack occurs. Others are light or picky eaters. The bottom line is there is not perfect time for everyone to have snack nor is there a perfect amount to serve each person.