political speech as literary genre

i don't really understand why the average political speech isn't better. it's constructed like a laundry list or something, kind of moving from one theme to the next. i would think that the first thing to do would be to give the whole thing a single rhetorical or thematic focus. develop a single idea or metaphor, and then work in what you can in relation to it. even jesse jackson building 'keep hope alive' is better than these states of the union or convention speeches, but there are many ways to make a speech a single thing. obama could have built that speech brick by brick on citizenship or whatever it may be. not every speech has to mention wind turbines. i just don't think the average speech is actually written as a coherent single thing. this reflects the participation of many pens. but the most you're going to get in a speech like that is a list of sketchy policies and isolated good lines.