> Ignoring the stabbings and shootings, the children are not disciplined, properly supported, or permitted to excel. The speed of education moves at the slowest students and interrupted by the most disruptive.

"Smart" and "disruptive" are in my opinion at least uncorrelated, perhaps there even exists a non-trivial relationship:

In my observation often children who are either much less or more smart than the average are the more disruptive ones, though the children at the two the ends of this spectrum differ in the kinds of disruptions.

Bell curve. Top 10% of smart are trying to do the work. The bottom 10% are avoiding the work, finding a way to kill their boredom through disruptions. That middle 80% cannot stay or complete tasks because of the disruptions.

Segregation by IQ, GPA, or test scores would help those who are capable of achieving what is possible.