The American oil producers are actually losing money or just breaking even on many of their drilling operations currently. This might seem like it does not make sense, but for many of these companies, the losses associated with this are directly related to their attempts to keep their employees employed. They are eating through cash reserves quite quickly. While this may not effect the very large oil companies like Exxon that drill world wide, this definitely affects the Sandridge, Devon, Chesapeake and smaller sized producers where the majority of their oil production is in the United States.
Sure, but they are going to bust, not keep pumping for 5 years. That is, if they can't actually make money at $40 (I am only a very casual observer, but it seems to be the case that some of them are at least in that vicinity).