I don't think we'll ever see SJC turn into the EWR vs SFO's JFK like setup.

But if you live South of the Dumbarton on either side it's more convenient to hit up SJC and plenty of ways service will grow there. Kind of like Orange County vs LAX but without the curfew.

As for market size it's less about wealth unless you're trying to support a specialized product like PS.

Most biz travel is on other people's money - so being convenient to lots of people with good income but not quite wealthy is sufficient.

Though I agree the biggest wealth belt is MP/PA down to Saratoga / Los Gatos.