This seems like a really valid and important point. Yet companies who do build their entire business on other companies' info / APIS (Think Greplin, Trendrr, Tweetdeck, etc.) still get tons of interest from investors. While it is easy to realize the importance of developing an independent business when commenting on HN, I think the startup community as a whole needs to start displaying this in its actions.

Once more large internet companies realize that their users (both of their services and API) are not necessarily their customers (Think Twitter's denial of new 3rd party clients), the API free-for-all which we're experiencing right now will dry up, and we'll see at least one of the companies-who-are-built-on-other-companies fail. This might be the kick in the pants that the startup community needs to realize the importance of building unique, independent businesses.