That's because we've figure out how to monetize it. The "for profit prison', means it is a persons patriotic duty to be incarcerated, to help drive the economy.
Or perhaps we Americans are much more prone to violent and illegal activities (gun crimes, theft, fraud, and so on...) that are likly to get you incarcerated? Americans as a whole are much less inclined than many European societies to actuall participate in scoiety with a goal of "getting along". We are an "I've Got Mine, Fuck You" sort of people.