There's also enormous risk embodied in the sky-high real estate prices in CA and NY, namely that they might not continue appreciating, or could even flatten and

There's also enormous risk embodied in the sky-high real estate prices in CA and NY, namely that they might not continue appreciating, or could even flatten and drop somewhat. The prices in CA are driven by the extraordinary scarcity of housing relative to the demand created by the booming tech industry. Real estate is priced at the margins, and if the tech outflow accelerates it could tip to a new lower baseline relatively quickly (see places like Miami and Las Vegas in 2008). If that happens you risk being underwater by substantial amounts.