I had a neighborhood friend in the 1950's who was held back in school. I'm sure he thought he was dumb, but he wasn't at all. I found that out when he watched me do my algebra homework. He'd never been exposed to algebra - too "dumb" - but he asked me what I was doing and after I explained, he was solving quadratic equations as quickly as I was.

I lost touch with him but recently found his obituary. He died a few years ago, but the obituary told me that he had owned a succesful construction company and left a large family.

Self employment is often a good refuge for people who don't "fit", whatever the reason. It was for him and it was for me.