It may have been necessary to run the retail side, but it’s now more than half the profits.
Amazon Web Services (AWS) is significantly more profitable than Amazon's retail business, though retail generates more total sales. AWS's operating income is a much larger percentage of Amazon's overall operating income, [according to Business Insider]. For example, in one quarter, AWS accounted for over 50% of Amazon's operating profits despite only representing 15% of total sales.
That’s what I’m talking about: leveraging the assets into an entirely - but connected - line of business. Any fool can go out and buy a different business (and often fail at it); turning a current asset into a complimentary one takes skill. (Apple computers —> iPod —> iPhone) (Amazon.com —> AWS —> logistics)
I see them doing that now with their delivery network. As they have more capacity, they are able to sell it to others (exactly what AWS did) and create a complimentary business, and possibly a behemoth capable of competing with UPS and FedEx. The second half of this post is where I first saw it: