While some with potential may be alienated by standard schooling (and I'd blame lack of resources to tailor curricula to individuals more than schools taking the wrong approach), it is not clear to me that individuals with imagination and excellence do not generally thrive in the current schools.

To take your example - "They ran funny, batted strange, throw strangely. They played better because they were different." Why do you not think they would have done even better with better running techniques, better batting postures, and better throwing motions? Quarterbacks are an example in which if they are good enough, they retrain them to thrive in the pros. Persisting with quirky techniques is rarely the way to excel. Adding to the standard material rather than reinventing it is the much more common and productive way to go.

While I did not have a particularly impressive attention span nor self-discipline, and had plenty of strange and ineffective habits as an adolescent, it wasn't hard to succeed in school. Seriously, how much effort did those high school math and science classes take to do well?

I'd argue that difficulties in school portend difficulties in later life, and rather than schools being an unfair filter repressing true talent, they represent just one of the sets of challenges we face throughout life, and tend to train us to handle the reality of dealing with society.

As far as the "dumb thugs", I'd agree not everyone wants to spend much time learning, preferring just to get stuff done, then relax, but what's the harm? Except to our egos that revel in science (with the exception of those occasional antediluvian policy decisions).