In the business world, you cant be flipant about paying your debts. Its very bad business. To retain any measure of credibility, you must always at least act like you tried everything you could to pay your debts. You are right in that these companies could blow everybody off but then the lawsuits would fly and the bancrupcy fillings would follow. Then you face the judge and if he sences a cheap skate scoundrel standing before him, he will order remedies much harder than the standard humble pie he deals with.
When your hat is in hand, you dont act like Rob Blagoyovich. You act like those 3 Auto CEOs you saw on television taking their spanking. I wish somebody would spank me or even beat me silly for 15 billion dollars.
And by the same token, the government doesnt want to do something that scares away future investors, or the government may be warding these companies far longer than they bargain for. Fiat has already expressed interest in Chrysler, but its all dependent on the government first adequately shoring them up.