[ltrcola]

I'd argue that it's not just PayPal though, although they've played a part for sure. Credit cards in the US are ubiquitous and offer a very high level of fraud protection that consumers are used to.

Of course, that fraud protection (and the multiple points & cash back systems) are all covered by overhead in the system. Merchant fees are quite expensive, although the consumer never usually sees them except for small things like cash discounts or minimum transaction amounts at small businesses. There have been some interesting court cases about the ability for merchants to pass those fees onto their customers.