But he isn't posh, one of the few drivers on the grid who doesn't come from big money. He did go to a good school but has a pretty normal middle class background.
Russell, Occon, Bottas, Hamilton aren't from wealthy or connected backgrounds (that I can remember). Most of the drivers do or they have heavy sponsorship backing like Zhou. They have families who gave up a lot to get their kids into racing, like Anthony Hamilton did.
One of the reasons Perez is staying is due to money. He has a lot of very wealthy people backing him.