Any sales manager knows that incentives radically change behavior of their team.
George W. Bush is president because his team better understood incentives than his opponents. Bush won two of the closest presidential races in history and incentives most definitely affected the spread.
The Bush campaign paid their media advisers a flat fee in both the 2000 and the 2004 race. Typically media advisors are paid as a percentage of their spend. This encourages them to spend lots of money so that they can earn millions of dollars in commissions. This has perverse incentives as it encourages media advisors to focus on television which might not always be the best choice. It is probably why both Gore and Kerry (who paid their media advisers the traditional way) overspent on TV ads and under-spent in other mediums. In 2004, the Bush campaign focused much of its dollars on organizing and away from TV – partially because senior campaign staffers were mainly incented to win and not financially incented to run more commercials. If Gore or Kerry had changed the incentives for their media advisers, we might have seen a race with a different outcome.