Post Office analogy to Obama/Pelosi Heal care Public option

The proper analogy, and one that Obama did not make:

At least part of the Post Office's problem is that it must deliver every piece of mail at an average price whether it is profitable or not.  UPS and FedEx can choose to whom they deliver and the prices they charge for delivery.  The "Public" option will suffer the same fate because everyone must be insured.  This, to me, is the proper analogy; one that Obama didn't make because it hurts his case.