How much of the perpetuity is the uncertain funding faced by researchers in the field? The same can be said of supercomputing which directly feeds fusion research. Instead of long term funding, we get 1-2 years of off and on "kickstarter" projects. Long term funding set aside for things like fusion through 5-10 year commitments could improve the outcome. You're totally right though, fresh water as you get to in the end is a direct result of power. Everything comes down to power. As we move from a factory industrial society to a additive manufacturing society this will become even more true. Those who have the power (literally, like electrons) will thrive, those that don't...will look like the middle east in 100 years.
Food is literally equal to power. It's fuel. The joules have to come from somewhere. And "micro-machines that can produce molecules on demand" would be life. If you have tons of free electricity you can turn it into food with greenhouses and grow lamps. As it is, it's usually cheaper to use solar directly.
