Like a casino only the house wins... and that is Google.
For Google to win, the advertisers have to win too.
Google has little to gain from advertisers who spend themselves into oblivion then have to stop their ads. Google will make the most money by far from advertisers who have well-managed AdWords campaigns that turn a profit and run for a long time.
For just about any business outside the wedding sector, the big profits are in the repeat customers, and AdWords is no exception.