A while back, I posted a letter from the president of eBay about how they are having to perform some strategic back-pedaling to recover from their sense of supremacy in the online auction world. [here]
It is true that other companies have all of the apps that Google has; the genius in Google is that they will be unified on a single patform, tied together to deliver a fully-realized work/home/play/buy tool. Why go anywhere else, when Google can find it for you? Which is faster: Amazon’s native search, or Google’s search that points to the appropriate link on the Google site?
Google drives people to e-commerce sites. It is how buyes find sellers. All players need to realize this, and get on the bandwagon, or they will get lost in unfriendly, and unprofitable, territory.