The sleepy suburb gets the commercial revenue from having a major tech firm, and then most of the workers leave and the residentialists get to keep the revenue for their city services.
The service workers who had to drive until they qualified, they go home to more far-flung suburbs with financial problems and poor services. This is segregation by deliberate policy.
But it’s starting to fall apart. When there were still nearby orchards to pave to put up parking lots, the new homes were cheaper than they are today, and the rich suburb could still hire workers to provide the services. Now that there’s not enough room for both new single-family homes and parking lots, and they are refusing to allow sufficient multi-family housing, the housing supply is not keeping up with demand and the service workers are increasingly refusing to take the jobs. This is manifesting as chronic short-handedness in the schools, in the police and fire departments, in the transit agencies. By greedily holding onto commercial revenues, these suburbs are destroying their own ability to provide services.