I think the author's point is that the internet needs a payment system in which the customer doesn't need to put in their credit card. That's why he's saying Amazon could be the default payment provider (since almost everyone has an Amazon account).

So doing what you suggest would completely defeat the purpose of what he's proposing.

Thanks for clarifying my point. That was exactly what I meant.

Having experiences in mobile services, payment was not a problem. It is something users don't even think about. However, on the Web, the act of paying is too obvious and requires too much effort.

Doesn't almost everyone have a Paypal account?

No, though it seemed like it at one time.

The vast majority of people have never bought anything online, so there's lots of time for disruption in this market. :)

I don't :)