This is no great mystery. There’s a segment of the population that wants 1) zero taxes and 2) full govt programs for themselves (screw everybody else), and will vote in any politician who promises them that. The GOP, with their trite slogans, can win elections – but they can’t govern, because their ideas don’t work (aren’t based in reality). Stuck on Stupid.
For another articulation of this view, recall that even when House Republicans passed Ryan’s budget Friday, NBC News’ Mark Murray marveled at their political gambit: “Either the normal rules of American politics have changed, or Republicans have walked into an electoral buzz saw–on a Medicare plan that won’t pass the 112th Congress and that many of them didn’t campaign on in 2010.”