Sure, but water is hardly the only input they're optimizing for.

They're reducing the need for pesticides and fungicides by controlling the ambient environment around the plants.

Reducing the need for fertilizers by optimizing growing conditions and limiting runoff and waste.

Basically - the attitude there has been: "Build the right environment for the plant" followed by a focus on efficient (and therefor cost effective) inputs.

We aren't building the right environment, we're just dumping inputs (pesticides, fungicides, fertilizers, water, etc) on the growing area and calling it a day.

Which is cheap on the up front capital costs, but much more expensive over the long term, as you end up needing consistently more inputs over a long period of time.

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Basically - I'm arguing that the up front capital costs likely are worth the returns to you get in efficiency, but farmers in the US are not incentivized to make those investments. Or perhaps more realistically - can't afford those investments on their current operating margins. Which is why we likely will want government programs focused on this.

> They're reducing the need for pesticides and fungicides by controlling the ambient environment around the plants.

Not just the ambient environment. When you go soilless through hydroponics, you eliminate a lot of soil borne disease issues. Even soil control through pots instead of direct ground contact prevents a lot of problems wiggling around.