Ahh, I see your point. We might be happy enough making showers more expensive, but making farming more expensive has a huge ripple effect, and there's no elegant way to do the one without the other (though we already have and use inelegant ways of subsidizing water use on farms, as Telnar noted).

The air-mix shower that tricks you into thinking you're taking a regular shower is the nicest idea from the WSJ article. Assuming it works and isn't just like Jurann's misty-shower that doesn't feel like it's rinsing you off. >:)