Before Chrome & Chrome OS : You & me -> OS (Windows, MacOS X, etc.) -> Browser (IE, FF, Safari, etc.) -> Google Search -> internet / webapps
Perfect world for Google: You & me -> Google (OS, browser and Search) -> internet / webapps
Cellular phones, and the iPhone in particular, bring the threat one step further. Because what should be webapps are simply Apps on the iPhone, making Google a complete outsider instead of the gateway toward mobile apps. When you look for an iPhone App, Google is an outsider. A second choice after a failure with the iTunes Store Search.
I see Android as the answer to Apple standing between Google and its customers on the mobile market. And Apple standing in the way today sounds a bit like Microsoft standing in the way back in the 90ies...