Because they only make those folding mats 36" long?
Because naps change as puberty approaches?
Because children used to be seen as cheap labor for the farm?
Because Germans invented kindergarten but somebody else invented the rest of the grades?
When snack time was fired, nap time walked off the job?
Because they would have to keep having school until July to make up the time?
Why don't teachers have to do something else during the summer, anyway?