What a horrid story of US medical tunnel vision and consequent incompetence. I am so sorry you went through all that.
Imagine the health cost savings if your son had been correctly diagnosed on the first or second presentation!
And you? It took a long time for you to get that vital diagnosis, also. How did the world handle you before that?
What do you think might have changed or been avoided if you had been diagnosed in Kindergarten?
[I have wondered this about myself, too. I had a difficult time in normal school. It was not until I was in my mid twenties and my university went over to open book "continuous assessment" that I finally shone. My rote memory ability is quite weak and fickle compared with my comprehension and information processing abilities. I went from an average to poor examination candidate to a superior performer almost over-night :-) ]