Once an employee has a certain amount of financial security and a track record of making things happen (traits shared by a number of Google employees), the employee might be motivated to leave for a startup where there is an opportunity for a big payday. The Google awards provide an opportunity for a big payday while staying at Google.
There's an absolutely gigantic literature in management, economics, and other areas on pros/cons of bonuses and specific bonus schemes in all sorts of contexts, though, so I'm not sure it's fair to say there's any consensus on them being considered bad for knowledge workers. My recollection is that there are some arguments about it coming from an intrinsic/extrinsic motivation perspective, arguing that knowledge workers are most motivated intrinsically (because they like the job, find it engaging, like problem-solving, etc.), and that extrinsic motivation like bonuses might not help, or might even harm motivation (there's evidence from some psych studies that the presence of extrinsic rewards can reduce previously existing intrinsic motivation).
The Founders' Awards aren't really a "bonus scheme", but more like a Nobel Prize (which may or may not be a good way to motivate "knowledge workers"). Regarding intrinsic/extrinsic motivation, I can't help but feel it's oversimplifying things: where does social recognition fall? I'd need to think a bit about it before having a coherent answer.
Maybe my assumption that this is a widely held belief was wrong.
It seems to work for Google. I'm just curious what it is about their implementation or culture that makes this the case.
This TED talk summarizes the book: http://www.ted.com/talks/dan_pink_on_motivation.html
Speaking generally again, I think Pink's ideas oversimplify "work" when they label it as "creative" or "manual". This goes doubly wrong when if we try to incentivize one or the other. At least from my experience, successful projects require both great creativity and a hell of a lot of grunt work.