Google Shopping Express expands to Manhattan and Los Angeles

Somewhat different product but all big supermarket chains in the UK offer home delivery - depending on what time you order and how busy a day is you can even get yourself a same-day delivery.

Tesco, Asda, Sainsbury, Morrison's (?), and there's even some online-only retailer that delivers in London and possibly other metropolitan areas.

Anyone have an idea why this concept is not offered by the big chains in other countries (at least those that I am aware of)?