You are so right. So many kids would do better - I think a lot of the special education mess in particular is directly related to institutional issues and have nothing to do with the abilities of the kids. A famous homeschooling family, the Colfaxes from California who had 3 of their 4 sons attend Harvard after homeschooling, remarked that the boys were eager to hit the books after spending a few hours doing chores on the family ranch.
I'd like to correct one point, however. Kids like mine (and I do not flatter myself that she is an exception) tend to have very definite and positive ideas concerning their education and life. I don't do most of the planning - she plans and I guide some of the choices and decisions where I see some deficiencies. She takes ownership of her choices and her life. People like me educate their children as much in the philosophy of learning, a look into possible futures and what it takes to achieve them, consequences of choices, and an appreciation of "the good/moral life" as we do in providing academics.
I think you wrote this really well. These were my intentions as well while raising my two sons. Except I wanted my kids to be able to "fit in and survive" the American national public school system.
But that said, I didn't just throw them out there. I knew the schools had many problems. So I participated in the PTA and was able to get positive changes made throughout their education. Then in high school I was encouraged to take a more hands-off approach but of course I was in the background guiding them. One of my sons was in the "gifted" education program in which I was able to help shape the curriculum. I tutored math in my son's grade school so I could be right there with him.
I'm proud to say both my kids are respectful, happy and well-adjusted, have part-time jobs while going to college, and generally all around good citizens. My oldest son just graduated from a major university in computer science, a subject he loved all his life.
So my educational philosophy is the same as yours, however, I know I could never have provided the opportunities for my kids like you did. I chose to work within the system and try to improve it as much as I could. A major bi-product of this type of educational philosophy is raising kids that are self-reliant, peer-proof and can make good choices on their own. Maybe that is the only important result anyway no matter how they get there. LOL!