$20 postage stamps, maybe

The US Postal Service may be forced to go out of business. I am confused by this. They lost over two billion dollars last year, so they are in the red. Two billion dollars is nothing in government terms. AMTRAK the government passenger rail system, lost over 5 billion dollars last year. They also lost 5 billion the year before, and every year that they have been in business. They have never made money, or been anywhere close to being in the black, yet they never go under. The post office has nothing to worry about.