Okay, so first, in order to make this work you'd have to outspend Google. I mean, for Microsoft and pals (you know, anybody who can afford to spend a billion+ dollars to topple Google), search is a nice business that they want; but for Google it's their core business (well, it's what powers their core business). You'd need someone else willing to bet their company (or someone who dwarfs Google, maybe GE or BP wants a search engine really bad?), because the stakes will be that high for Google. At the first sign of a strategy like this working, Google simply shows up with a bigger check. You think it would be easy for people to lure Google away with a million dollar check? How easy would it be to convince them to stay with a two million dollar check?
Second, Google has lobbying muscle now. Assuming this is legal, it might not be soon. They'll probably outlaw it in an amendment to the next Puppies for Orphanages Act that comes through. "It's not Evil, it's Democracy!"
This strategy would have worked great before the IPO.