I'd only add one thing about that last paragraph:
"Parents also have to be clear about their own values. Children watch us closely. If you want your children to be able to stand up for their values, you have to do the same. If you believe that a summer spent reading, taking creek walks and playing is better than a specialized camp, then stick to your guns. Parents also have to make sure their own lives are fulfilling. There is no parent more vulnerable to the excesses of overparenting than an unhappy parent. One of the most important things we do for our children is to present them with a version of adult life that is appealing and worth striving for. "
Imo it is also helpful if you can convey the idea that the parental version may not be the only possible one worth striving for.
My parents were very good at making their own way of life- very academic, into music and arts but not sports, classical literature but not popular music, the sea but not animals- seem appealing. No harm in that: they are all pleasant things. But if we have a tendency as a family it is to close in on ourselves and think of our likes and preferences as some kind of moral principle.
This has not been helpful to me in later life.
And it made life terribly difficult for my brother whose natural tastes in music, reading etc were simply different from his parents'; for many years, he felt morally inferior, I'm not sure he doesn't still.
Whether you spend the summer reading or at a specialised camp is not a moral value, it's a personal preference! You can still stick to your guns on the subject, but make it clear which guns they are!
And once your children reach the age of understanding, make sure when you use the phrase "we" that you know who you are talking about! I still cringe when I hear my (much loved and loving) mother say "of course we don't like such and such" and know I won't have the nerve to say "well, actually, I think you are speaking for yourself there".