I think there's lots of contributing factors. Not just the politicians. We should remember a lot of what the politicians say and do is driven by what will help them get re-elected -- i.e. by what the populace in general thinks is important.

(I am not saying "oh it's not the fault of the politicians, it's the fault of the populace" -- see my opening sentence that I think there's a lot of contributing factors. And each of these can go several layers deep).