You cannot persuade me that this many parents are selflessly sacrificing their own lives to cater to their children in such a manner.
Some, and I'd venture to say a lot, actually do this. They love their kids enough to put their own lives and desires partially on hold for 10 or so years, or find a good balance to do the 'extra' things, before the kids leave the house as young adults. Some, agreed, will be the "Rob Lowe peaked in high school" parents living vicariously. But not all of them, and I'd say not the majority of them.
Some parents, too, are repeating what their parents did and are jealous, defensive, sensitive or downright mean about what their own kids do or want to do: you don't need all that, here's a scruffy $10 bat from the yard sale, quit asking, get in the truck. In short, they're pissed off because their kid is trying to enjoy being a kid with his friends and because the parent wasn't able to enjoy his/her childhood, they're hardasses about it. Have seen that before, too.
