Idle thought while vacuuming

OK all you finance and legal professionals who read this (you know who you are):

Listening to an interesting piece on credit derivatives from The Economist. The suggestion, which I think I agree with, is that there's nothing inherently wrong with credit default swaps and other forms of derivatives, but that people have radically underestimated the counterparty risk (a la AIG) and that causes the dangers that we're experiencing now. The fix is to require a central clearing house, similar to a stock market, which spreads that risk - this all makes sense to me.

But if that works, why do we not extend that concept to every form of contract? That is, if there's an inherent problem with bilateral or multilateral risks arising from contracts, then why don't we force all contracts to be pooled? Examples: if I'm afraid to buy a GM car because I don't think GM's going to be around to honour the warranty, isn't the answer that warranty contracts only be issued through a central clearing house of all automobile suppliers and spread that risk? Similar arguments could be made for things like multi-year cellphone contracts. Why do we think credit derivatives (or securities generally) are special in this regard?