People don't "want a monopoly." But they do want to order things in a way that is by no means a "minor convenience." Just going back to when Amazon was getting started, finding a book that wasn't in stock at your local store was a massive hassle and could take months. Today, not spending an hour running errands is not really a minor convenience. Again, I'm good with there being more competition--and, in fact, I order things from multiple places--but Amazon is often the easiest choice.