Um, no? The Twitter API is nice, so far, but I wouldn't call it complete (this coming from someone 2+ years into developing twitter apps). Even with the current Twitter.com feature-set, there are more things they could expose through the API. As more features are added, more API endpoints will be needed.
It's nice that other sites have "cleverly" appropriated the Twitter API for themselves (something that Identi.ca actually did first, I think, and was the real inspiration for other Twitter clients to allow custom API roots), but that shouldn't mean that Twitter themselves slow down when it comes to innovating/iterating their own API.
> If two companies with a significant number of users that share no investors or board members both support a common API, we can say that the API has reached Version 1.0 and is safe to base your work on.
It's nice that other sites have "cleverly" appropriated the Twitter API for themselves (something that Identi.ca actually did first, I think, and was the real inspiration for other Twitter clients to allow custom API roots), but that shouldn't mean that Twitter themselves slow down when it comes to innovating/iterating their own API.