Here's your answer right there:
>> In the 1970s, Raleigh began to see white flight from
>> city schools, as Syracuse did, but in 1976, the school
>> boards of Raleigh and Wake County took the bold step of
>> merging into a single Wake County school district.
Don't think that places like Buffalo wouldn't *love* to "metropolitanize" not just schools but all public services: police, fire, libraries ... but it seems a little disingenuous to ask this question when the answer is: because it was politically impossible to convince the suburban "white-flight"'ers to do it.
Buffalo has lost 50% of its population since 1950, yet the population of Erie County has stayed fairly stable. Everyone who could leave, did.
/jordan