> Around the country, as companies have returned to cities or promoted hybrid work schedules, many suburban office parks have gone the way of the drive-in movie theater and the mall.<p>This is a bigger trend. Fifteen years ago the YC companies might be headquartered in Palo Alto or another suburb, but these days many of the YC companies are in San Francisco. I think we are seeing a revival of cities on a scale akin to the flight to suburbs in the 1950s.