http://www.theverge.com/2014/12/15/7397505/google-might-build-its-own-buy-now-button-to-compete-with-amazon
Its bound to happen, they really already do something very similar with holiday insurance, so other products are coming.
Opportunity or cost?
>Its bound to happen
Totally agree, they have an army of Google Express employees just waiting to be more exploited. If they are really going to offer one click buying they are going to have a legal fight over the patent I'd imagine, but they have the money to do it.