Simplification seems very difficult because entrenched interests benefit from the complexity. Look at health care: it's not hard to imagine a vastly better and cheaper system than the US has (indeed many other countries have it), but even minor changes to health care will involve battling politically powerful groups, and the political risk is extremely high. Same thing can be said about the complexity of the tax code. There have even been HN articles recently about how it's not hard to simplify the tax filing process, but Intuit and other tax preparers lobbied against it and killed it.