Someone (outside of the Dev Team) posted a fairly high profile blog questioning whether jailbreaking was useful anymore given the rise of the App Store and whether the Dev Team was wasting their time. They didn't really talk about unlocking in their argument (it's not really clear, at this point, if/when that's going to happen for the iPhone 3G). They made their blog post with a poll, though, and the poll got a lot of support for the Dev Team's continued efforts.
I think the high profile app rejections also call for a continuing Jailbreak market. If someone comes up with a paid app scheme for a Jailbreak system such as Installer or Cydia, I think it would establish a fairly significant presence.
But just to be clear, the blog came from outside Dev Team and the Dev Team solicited feedback on it but didn't exactly indicate any interest in hanging their collective hat up. If ya want a link I can try to find it....