You have it backwards. It's the strength of their core business that enables them to make big bets on the future.
They've gotta know as well as anyone: in this industry if you milk your core business too long, it may become a dinosaur too quickly for you to react.
To elaborate a little, I don't see any attempts at other markets as a bad sign from google or as behaving yahoo-like as long as they stick to their core principles of simplicity for everyone, including the power users.
You have it backwards. It's the strength of their core business that enables them to make big bets on the future.
They've gotta know as well as anyone: in this industry if you milk your core business too long, it may become a dinosaur too quickly for you to react.