Suburbs are a (relatively) new invention, and the original reason to move there was "get away from the black people" not "tired of city and wants space".
It was made possible (sort of) by cars and freeways which made living 25 miles away from your job a thing that was practical (sort of).
That’s only true in a few places, there were plenty of places (like Seattle) that didn’t have many black people at all yet people still moved
to the suburbs.
The suburbs were mostly an invention of a post World War 2 housing and baby boom.
Suburbs were in part fallout from establishment aggression against Catholic ethnic enclaves in the cities. But mostly it seems it was encouraged as a civil defense measure:
"Though suburbanization in the United States during the 1950s is a well known story, scholars still consider postwar prosperity and basic desire on the part of the American people to move further away from problems of the inner city as its primary causes. While it is true that various factors contributed to phenomenal growth of the suburbs between 1945 and 1960, historians have thus far paid little attention to policymakers' fears of atomic attack as a significant factor in population dispersal. This article examines how sociologists, scientists, and other experts considered the reduction of urban vulnerability a Cold War priority, and worked to encourage dispersion of people and factories as a civil defence measure."
And, of course, many jobs moved or were established in the suburbs/exurbs where potential employees mostly lived. It's easy to forget that a city like Boston was still losing population in the 90s and had basically no tech jobs in the city proper.
It was made possible (sort of) by cars and freeways which made living 25 miles away from your job a thing that was practical (sort of).