To a certain degree this is true. I think the major reason for why we see a "winner-take-all" effect on the internet is because of data persistence. Usually the usage pattern for brick-and-motor stores is that you visit it, get what you need, get out. With online services, however, the more data a site has, the more useful it becomes (e.g., social networks or Amazon's recommendation system). I think people subconsciously realize this and start to focus on one attractable service over another.<p>On the other hand, the ease of dissemination of products/services to users via the internet makes it so that niche markets are more efficiently served. This is usually harder to do with brick-and-mortar stores due to locality constraints. So even though, there might be "one big winner" there seems to be a growing market for niche products.