I hate to break it to you, but your "economically illiterate people" might actually understand some fundamental social and political realities that you've not yet had the chance to reckon with. Not to mention the physical realities of water resources.
Your comparison to oil pipelines is nonsense. Where to start: privatization, a global commodity market, relative scarcity, massive extractive capex.... Sure, we built oil pipelines easily in the past. How difficult has it become? Surely the capital exists. Why don't we build more?
Nobody is talking about abandoning real estate.
The tragedy of people like you is that you provide a half-compelling distraction. People (cities/farmers/industry) need to use less water.
The longer it takes to get people to realize this, the harder it is to fix.