As someone who was in the 90th percentile, I can confirm that it wasn't a universal quality about my entire being. I got to be in higher-level courses where I excelled. Those are generally available, even in public school systems.
And just because I was good at math and writing didn't mean that I "deserved" to be in some separate system where I got the "best" of everything (with diminishing returns). When I eventually encountered people who were afforded just such a deal ("elite" private school in a wealthy area), they were far less impressive than the top college-level facilities they enjoyed as grade schoolers; it seemed like a waste of money that could have been put to more efficient use, as far as society writ large might be concerned.
And just because I was good at math and writing didn't mean that I "deserved" to be in some separate system where I got the "best" of everything (with diminishing returns). When I eventually encountered people who were afforded just such a deal ("elite" private school in a wealthy area), they were far less impressive than the top college-level facilities they enjoyed as grade schoolers; it seemed like a waste of money that could have been put to more efficient use, as far as society writ large might be concerned.