That isn't a tradeoff of EC2: hardware fails... I've had servers from actual unmanaged server providers have random failures and need maintenance or need to be replaced as well. Hell: I've had my hosting provider tell me they are moving data centers before ;P. The real problem here is just that Amazon has made the idea of putting your servers in the cloud so easy that people who don't understand that the servers don't run on evil magic are able to use them.