I don't understand any of this. Are the people being held back staying in pre-k for an extra year, or an extra year of tutoring?
I was in pre-k at 3, again at 4, same private school for kindergarten at 5. My mother then had the brilliant idea to put me into "the excellent" public school for first grade, where the kids were more juvenile and clueless than they were at pre-k when I was 3. I was writing, reading, knew math inside and out, and these kids were lucky if they could write their name.
I couldn't imagine not sending my child to school until they turned 6. I guess if you really want your child to be a clueless retard it's a great idea.
Then there was high school, science/tech school which was the second best public school in the city, where I met students from China and Russia who were basically coming in with backgrounds in calculus and physics while we were still learning geometry and trig. The US education system is going backwards, not forwards, and parents want their children even further behind. This country depresses me.