The Internet is the very definition of decentralized. Sure, Google might provide an easy way to search for what you want, but then you're directed to some half-assed eCommerce site which may, or may not, be trustworthy. Assuming they're legit, or you just don't care, you've got to navigate whatever checkout process they've got, fill out a bunch of forms with personal info, and if you're lucky they don't steal your identity.
Don't get me wrong, what Amazon is doing here is despicable. But let's not kid ourselves, Amazon got to be the size it is because people like being able to just find what they're looking for and buy it with minimal fuss and without navigating the god-awful clusterfuck that is eCommerce. The comparison to Wal-Mart is particularly apt. Not only because of the two companies desire to take over the world, but because Wal-Mart, like Amazon, has excelled in giving people what they want, when they want it, and at a lower price than any competitor. The fact that these kind of retailers are destroying local economies is the last thing on most peoples minds.