The guy grew the company 5x. I don't think attrition is the issue.
I assume he left because it wasn't his company anymore, it was run by the board. If the board can override his will as CEO and accept losing the CEO over office location, that by default means the board did not really value him. I would expect that hurts. Some things you can't prove with data, these are subjective decisions that fall into the realm of a CEO's responsibilities to look out for his team. It wouldn't be so far fetched to believe that Yishan felt that the board did not allow / trust him to do his job.
It's almost certainly not really just about office location.
Any real world class metropolis like Hongkong, Shanghai, Tokyo or New York would blow SF out of the water in the "cool, fun, sexy" department.
Compare Hong Kong, Shanghai, Tokyo, or New York City to Daly City and then tell me where San Francisco falls on the scale.
http://www.yelp.com/search?find_desc=coffee&find_loc=San+Fra...
The post-war American suburban drive was in large part driven by economics and policy. Mortgage subsidization from the 30s with the Home Owners' Loan Corporation and the GI Bill in the 50s made loans available to mass consumers, while the HOLC's discriminatory redlining policy and the deindustrializing of cities (driven chiefly by lowered shipping costs) caused dense urban areas to become less desirable.
Mixed in with this you also had suburban-oriented urban planning (lots of highways, little public transit investment), brand new car driving infrastructure, low energy costs, lots of cheap land to expand to and in the 70s and 80s rising urban crime.
If you were looking to live somewhere, you had lots of incentives to prefer the suburbs. Today, most of these trends (energy cost, crime, job markets) have changed course.
Daly City is a suburban hellhole. If “cities” like Daly were desirable places to live, Provo, Utah and Tacoma, WA would be IT meccas.
The traffic in that region guarantees an ungodly commute by car for anyone who wanted to stay in SF and drive to Daly for work (1 hour commute = $40k in pay worth in happiness http://www.npr.org/2011/10/19/141514467/small-changes-can-he...). The public transportation is… lacking.
I can’t speak for Yishan’s motivations, but if I were on the board, I would push for his replacement simply due to the talent attrition that would inevitably occur if he got his way.