1. You would try and buy your way out of a retention problem by giving everyone an across the board raise. Turnover is hard to figure out and stop. Sometimes you just have to throw money at everyone and hope that the turnover stops. It rarely does.
Google is managing people, just like every other organization, so you would expect lots of stuff would be the same. I don't actually recall other companies giving everybody a 10% raise (Google probably has more money than your company). I agree, that this is not likely to do much to turnover.
The possible impact in Google's favor is forcing others to pay so much that they can't afford to do so, and shrink or even go bankrupt. Especially small organizations. Yes they will use options, but salary is also part of the requirement.
I think also, anyone taking away that Google's other moves don't matter is making a huge mistake. Google's moves to create a great culture, let people work with other great people is helping Google. The draws of leaving for so many great people are high. If Google were to be less proactive in other areas the problems retaining people would be much harder. Some people seem to take the idea that people are leaving Google as a condemnation of their tactics. I think that is the wrong thing to take away.
Related: Google's Answer to Filling Jobs Is an Algorithm - Google's Innovative Use of Economics