Google cannot afford to lose time. It's in a technology race. I'm not saying this guy was worth it, but it's not impossible to imagine how they make decisions like that. Time is much more valuable to them than money.

I'm not saying it applies here, but it's the core of many cons that you apply time pressure on the mark. "You can make all of this money, but only if you act NOW! Everyone else is doing it, they're smart and successful and YOU want to be smart and successful! I'm not asking for more than you can afford to spend, and I'm offering so much more in return! BUT ONLY IF YOU ACT NOW!"

When you pay people $100million for the grand accomplishment of sweet-talking the CEO, you get... Google+.

What race are they losing? Google search/ads is a monopoly or duopoly. You don't need to pay execs $100MM to maintain this--just need to keep the DOJ off your back. The rest (self-driving cars, et al) is money losing window dressing.