Artificially planned mixed use "downtowns" (for lack of a better term) require some sort of anchoring force: location, food and shopping, employment, etc. If that force here is based on google doing something--and they fail or just stop--then the development will fail.

America is littered with these kind of developments. In growing markets with strong demand, worst case, you just turn the retail/office space into lofts and rent them. But in areas where demand isn't high, you get empty strip malls.

And if all google is doing is building apartment/condo buildings in a hot real estate market, this isn't some digital moonshot vision of the future. They are just building apartments in a can't lose environment. Anyone can do that.