So can rationality work on a large scale? Arguably, it always does work. I rarely hear political or social arguments that are obviously (to everyone) pure hokum. If you look at how the last 4 U.S. presidents campaigned, it was always on "save you money" talking points and "less waste, more justice" platform. All rational things in the mind of the average person.

Sure. What's not rational is to believe that politicians will deliver on the promise of reducing waste. All politicians say they will do it, and have done for a long time, but governments are not noticable less wasteful than they were 50 or so years ago.

It's therefore irrational to believe a politician when they say they will cut waste, unless they say in detail how they will do so (which they usually don't).