I don't claim to be an expert but I can see one very simple cause for the problem.
Governments, especially in the US, aren't in power long enough to enact the long term plans that might potentially get everyone out of the mess.
Say you set up a ten year plan with a Democrat President, it's not perfect, but it'll go a long way to solving the problem. However, the ten year plan needs to be followed up by a fifteen year plan to best capitalise on the ten year plan.
Presidents are in power for eight years (basically), so any plans they put in had better be understood by everybody to be the only solution to getting out of the hole. You wouldn't even get to the end of the ten year plan before the President gets changed.
Simply put, this is an impossible situation. Democrats and Republicans disagree so much on the very base issues like the economy that no long term will ever be put in place. This isn't even acase of 'the situation will get so dire that they have to work together.' Marx put it best 'every decision is economic' which means that politicians need to have their strongest views where their economic policy is concerned.
To add to the problem, as if that wasn't enough, are the public, most of whom don't understand economics beyond 'I have enough money to buy what I want, therefore I'm happy.' They don't care if the money is technically not theirs because it's being distributed by a government that's borrowed the money it's giving to its citizens from banks and other countries, because for most people's view of economics, having the money in hand is all they need. So while the most important policies in the country should be economic, Presidents will often rise or fall on Foreign Policy, Education programs, the Justice system. No one wants to be told by a President, 'things are about to get real tough, and we need to country to just trust us.' That President would be out after only four years of his ten year plan.
That's the source of why the problem is so hard to fix. And it's not limited to the US either. The first thing the Conservativs did when they came into power was start changing all the long term Labour government plans, just like Labour did when they came into power.
Politics and economics should never be short term, but for various reasons, the people like to change their politicians in five year intervals. There is simply no time for any realistic forward motion on anything.