Google does have lots of money. And lots of success. But they're really only been around 10 years - not forever like most monolithic companies.
And their business model can fail, and fail FAST. To get users off of MS over to linux you have to chip away slowly. To get users off of Google to another SE it takes nothing more than a change in consumer mood and a grassroots movement, and about 3 months. Google can disappear that fast.
They seem to be alienating their most influential users these days - webmasters and advertisers.