Doesn't that just mean you're following the wrong people? It's not like Twitter forces you to listen to (or continue to listen to) people when you're not getting value from them.
In the end, it's what's valuable to you. If you can't (or don't want to) find a group of people to follow that you find interesting, helpful, or whatever, that's fine. Just because you (or sharpn, or my wife) don't find the service valuable doesn't mean that there's no value in it for anyone, though.