What happened was busing.
Beginning in the 1970s and into the 1980s, every major city in the US decided to destroy neighborhood public schools in the name of racial equality.
Instead of going to the elementary, middle, or high school down the block, school children were shipped miles across town, spending hours a day on a bus at the cost of billions of dollars.
Black kids from the ghetto were sent to "good" schools in white neighborhoods; white kids were bussed to "bad" schools in the ghetto.
This caused social upheaval and accelerated "White Flight". Parents who could afford it fled urban school districts and moved to suburbs or the country. Or they enrolled their children in private schools. Incidentally the homeschooling movement began at this time as a direct response.
The social fabric of American urban neighborhoods disintegrated because good schools were the linchpin to a good neighborhood.
High school football games, school plays, bake sales, PTO events. Kids would go to the same schools as their parents, would have the same teachers even. Local businesses were counted on to be school boosters and in turn often provided employment to kids attending high school.
 Now the question was asked at the time, why not simply send "good" teachers from "good" schools to the "bad" schools in the ghetto? The reason was because the teachers unions threw a fit and educators flat out refused to be transferred. Teachers with seniority had no intention of commuting across town to the ghetto. Far better to ship the kids off instead.
As a personal anecdote, growing up in West Seattle my parents had hoped to send me to EC Hughes Elementary (pictured) which was the same school my father attended. We lived a block away. I would then attend Denny Middle School and Chief Sealth High School, just like my parents and all of my aunts and uncles and cousins before me.
Instead, the Seattle School District that year decided to implement busing. A controversial decision.
Rather than having their kindergartner shipped off to Beacon Hill, my folks decided to sell their house and move to unincorporated King County so that I could attend a neighborhood school.
Tens of millions of parents did the same.
An American tragedy.