i think it's a valid question. netscape went from total market domination to nothing in a few years. granted MS pulled from under handed moves to make it happen that would be a LOT harder to do this time around, the scene is set the same. google innovates and takes market by storm, MS puts out a few non starters, eventually refines it's product to take the lead.
1. Netscape wasn't a public company as well run as Google is today.
2. Underhanded moves can be pulled by anyone, and Google is as smart as if not smarter than MSFT, which still has a lot of old blood from the 80s running the show.
3. Microsoft could also end up trying all the time to play catch up to Google, just like how Linux Desktop is touted as always(not my opinion) playing catch up to Windows or how Windows plays catch up to OSX and still ends up shabby or how Mono plays catch up to Microsoft C#.
The whole bing(TM) backronym of Bing Is Not Google, can also mean that it can never be as good as Google.