Since Lewis writes primarily on business, business folks will undoubtably read Moneyball with an eye toward picking up some pointers on how to run their companies. Some will completely misunderstand what Lewis discovered about major league baseball and beefheadedly apply their new "knowledge". The lesson of Moneyball is not that there are potential employees out there that are cheaper than your current employees. That's the holy grail of large American corporations and exactly what they would want to hear.
As Lewis reports, what Oakland actually did is a) measure player statistics as objectively as they could, b) identify players that perform well in those statistical categories, c) discover that the players they valued were not valued by other teams and were therefore relatively cheap, and d) went out and got the players they wanted at bargain prices. As much as the business person would like to skip directly to step d, it's impossible to determine if that will actually be effective unless you do the a-c analysis first.