All the news about where Google is rolling out GFiber seems to indicate they're getting their feet wet with smaller communities first, which makes logical sense in many ways.
On one hand the logistics of managing smaller municipal networks is easier, the politics is a lot less murky, and they establish a history of cooperation and reliability.
Where they start to ramp up in cities with >1M people is a mystery though, only time will tell. It may be Philadelphia, Cleveland, Atlanta, St Louis, Minneapolis, or even Dallas.