Using the analogy of a vehicle insurance; you could see how this might become a problem for the insurance companies if the government forced them to pay out to customers no matter what. People would never purchase vehicle insurance until after they crashed. Insurance companies would go out of business.
In the same way, if people know they are guaranteed coverage then nobody in their right mind is going to invest in medical insurance until they get sick/injured.
There was a post on reddit under r/explainlikeimfive that summarized the effects of Obamacare very well. This is that post.
This post has been edited by dorknexus: 28 June 2012 - 01:14 PM