I felt that discussing alternate business models was outside the scope of the post for 2 reasons: 1) I am an outsider, and no one understands what could or could not work better than the people working at Twitter. I am not sure what the pro-API camp inside of Twitter had in mind. 2) Debating which model would work better would derail the points I wanted to make in my post.

I do think there are several large cloud companies that have both their "native" UI and rich/powerful APIs. For instance Salesforce, which my company both pays for & extensively modifies and extends via their API. Given the attention this post has attracted I may write a followup post just on this topic.