The public school system in the past never worked any better than it does now. Arguably it was worse in the past.
...There's a lot of both selective memory and self-selection among people who talk about how the urban public schools worked so well back then. They invariably were among the *minority* for whom the schools worked.
The challenge in this sort of debate is that we do not have reliable ways of evaluating school performance. It is hard to know what to treat as exogenous and what to treat as endogenous. When I was growing up, the kids in the worst ghetto school would have been afraid to curse in class. Now, cursing is routine in the fanciest schools. But it's hard to know whether schools per se should be accountable for that. Or whether it's an important issue.