I wouldn't go so far as to say that no card offers such a benefit, only that the coverage may be very limited compared to that bundled with cards issued in other countries. I think one reason is that insurance is largely a state regulated business in the USA, and a specific insurer may not be licensed to offer coverage nationwide, but the card issuer wants to offer cards everywhere.

Here is another American Express link. Look in lower left for "Travel Insurance Options". Some of these are "per trip" products, but Travel Medical Protection is annual coverage.

http://www134.americanexpress.com/tr...ype=localcolor