No one is asking whether the overall population of the Bay Area is holding steady. They're asking whether the number of entrepreneurs is holding steady. You do

No one is asking whether the overall population of the Bay Area is holding steady. They're asking whether the number of entrepreneurs is holding steady. You don't need new construction for a Facebook developer-drone to move out of the Bay Area and an entrepreneur from Kansas to move into their apartment. So there's no reason to assume is is anywhere close to 1 entrepreneur leaving for each 1 arriving. And we're back at the original point: without any numbers who knows what is actually happening? What's more, even small differences become big when you compound them across the total population and several years. Say the ratio is 1.02 arriving for each entrepreneur leaving. And 1,000 leave every year. After just five years you've got 40 new companies. Many cities would kill to have 40 new companies founded (relative to their baseline formation rate).