So the tech industry didn't push prices higher. It was drawn to places that were already expensive. This may have been because these areas had major research universities, technically skilled workers, computer manufacturing industries or nice climates. Kolko points out that the year-over-year increase in home prices in tech hubs is actually in line with, not ahead of, the national trend; that is, after one accounts for the local severity of the housing bust.
Looking 10 tech hubs—San Francisco, Oakland, San Diego and San Jose, Calif.; Seattle; Middlesex County, Mass.; Raleigh, N.C.; Bethesda, Md.; Austin, Texas; and Washington, D.C.—the average price gain in 2013 was 13.4 percent from 2012. Compare that to an 11.4 percent gain for the 90 other large metros. The gap, Kolko argued, has to do with fact that tech hubs had steeper price declines during the housing crash but have fewer homes stuck in foreclosure today. If you adjust for that, the gap disappears.
(Read more: All-cash offers crushing first-time homebuyers)
Still, there has been growing animosity, in San Francisco especially, that the influx of workers from Google has made the city increasingly unaffordable. Affordability actually varies pretty widely among the top 10 tech hubs. Just 14 percent of homes in San Francisco are considered affordable (based on median metro household income) compared with 60 percent in Raleigh, Bethesda and Washington, notes the Trulia report.
The reason San Francisco is so expensive may not be the high-paid tech workers, but a far more old-fashioned scenario: too little supply amid high demand.
(Read more: Cold weather puts chill on home sales)