Students should not be doomed to life of poverty because their parents didn’t have the financial freedom to opt out of a failing school.
Every school has some good teachers and every school has some bad ones. This should not surprise anyone. We've had good and bad Presidents, good and bad workers at Walmart, good and bad CEOs of major companies, not to mention good and bad drivers on the highway.
The school isn't "dooming anyone to failure," but its students are behind the eight-ball - and not necessarily at the fault of the school they're in.
The "school" isn't failing the kids in a good teacher's class. The smart kids who bring up the averages aren't being "doomed" by the school - they'll get where they want to go. What you get out of education depends on what you put into it.
There are good teachers and bad ones. You can get an education or not and the school is only a part of it. In my school, your school, inner city and suburbia.
If you select the students, you can get great students from any socio-economic level, just like KIPP. If you are forced to accept anyone, then that's what the public school gets. It doesn't make the school any better or worse, but it does lower the averages.
An individual is not defined by the average. You can always find an average from the individuals but you can't define an individual from the average score.
You can get a bad education (or just a hangover) at a good college or a good education at any college (or you can get a "Gentleman's C" at Yale but that costs money).