The market is that because the numbers say that's where the market is. What's wrong with selling your book at Wal-Mart is that the numbers say you will not sell enough to make a living.
As for "what barrier," well, consider a website that is visible on Bing but not on Google. Go ahead and tell them "but visitors have no switching cost!" The cost of not being visible where customers are actually looking for you is very high indeed.
> As for "what barrier," well, consider a website that is visible on Bing but not on Google. Go ahead and tell them "but visitors have no switching cost!" The cost of not being visible where customers are actually looking for you is very high indeed.
That isn't a cost to the customer, it's a loss to the supplier. The problem suppliers have is that customers have lots of competition to choose from. A customer might have equal preference for two books that each cost about the same amount and therefore choose the one which is easier to find. That choice makes all the difference in the world to the publisher but negligible difference to the customer.
That's why the customer places such little value on searching for alternatives. Because there is negligible harm to the customer. If there would be customer harm, the customer could instead exercise the option to spend only the few seconds necessary to find the book at another retailer. Unfortunately for the supplier, there isn't, so the customer doesn't.
> The cost of not being visible where customers are actually looking for you is very high indeed.
Does it constitute a monopoly though? I doubt the folks at Google love Amazon.com but if this became the sufficient to declare Amazon.com a monopoly, then the obvious next step is to immediately declare Google web search a monopoly. With over sixty percent of the eye balls (the last time I read any stats), Google would be in the cross hairs.
Even so, what barrier do customers have to purchasing at some other online retailer? Where's the insurmountable switching cost?