The final answer to the perennial question "What is algebra good for?" is found in the success or failure of society as a whole. The same can be said for many other oft-questioned values, like "What does it matter if I'm a hypocrite?" In truth no-one really knows what the future will bring - it's always possible to construct a scenario where ignorance and irrationality will save society from extermination. But in the "horses, not zebras" sense it pays, I think, to play the odds and consider the most likely scenarios that put a society at risk: invasion, revolution, natural catastrophe, and then ask those questions again. Much of history can be read as a set of experiments testing various social theories, and the failure modes of not knowing algebra (Cambodia), or not caring about logical consistency or truthfulness (Russia) are well-known. Education is an insurance policy against a threat that may occur a generation or two in the future, and so the feedback loop is very long. This says, to me, that any change to education policy or practice should be very slow, incremental, and based not in aesthetics or ideology, but on the need for society's continued existence. It would be optimal to have many parallel longitudinal incremental educational experiments going on all the time, and then adopt the changes that bear fruit. It would be optimal to require that ALL educational policy makers be experts in history.