I think we need to expand our definition of "learning" - kids who learn to function in a group, explore various skills, watch/observe, and verbalize what they are seeing ARE learning. There is such pressure to learn facts or letters, with people thinking their kids are gifted because they know all the states and capitals by 2nd grade, or they read 4 grades above their age, etc. Preschoolers should be learning to hold a pencil or a crayon, not forced to write the entire alphabet.
We have a whole generation of kids who can't entertain themselves without a structured program (after-school or otherwise), who can't do any kind of critical thinking, and who don't function well in college because they don't have independent thought or the social skills necessary to live in a diverse environment.
My son is in his early 20s, and I took a lot of heat when he was younger because I refused to push him. He did an "extra" year of preschool and started kindergarten when he was 6 - and it had nothing to do with academic mastery. He never enrolled in a lot of structure programs after school - he did a season of Rec. Dept. soccer or basketball now and then, and he went to religious school, but otherwise he played with his neighborhood friends or (gasp!) played creatively on his own, building and designing with Legos or watching an old helium balloon float around the yard with different weights on the end of the string. He rode bikes and played ball and dug for salamanders in the woods. In high school, he discovered cross country and track, and only then did he do a daily activity after school. He was a great leader, captain of teams, and did community service projects.
He's now a highly social, skilled adult (civil engineer) with a wide circle of friends. He's creative, curious, and cultured.
Here's an interesting article -- we've got a problem on our hands in this country. http://www.washingtonpost.com/blogs/answer-sheet/wp/2014/...