What I did want to address though, is that while I like anyone discussing policy limitations, I think you need to add in what policy does well to give a complete picture. David Brooks puts it like this:
The influence of politics and policy is usually swamped by the influence of culture, ethnicity, psychology and a dozen other factors.
I don't think this gets it quite right. It's not so much that policy gets swamped by other factors, though this is sometimes the case, it's that we have a bad habit of trying to do things through policy policy can't do. It's not a genie in a lamp that can address whatever we don't like in our society.
Simply pointing out the state's limitations gets things somewhat wrong since it simply makes the state seem ineffectual. This isn't the case, the better frame is to acknowledge that the state doesn't always have the capacity to change the things we wish it could and it also has some capacities some of us would rather wish it didn't. The first step to developing good policy is to sort out which problems policy can address, and which are outside its power. This is something we do far too rarely.