Nobody is currently likely to go without. Just with less.

And the private sector is already doing the part it is actually good at in this case. Those desalination plants being built are privately designed. Even on the consumer level it is happening. Sales of rainwater capture and Grey water-reuse systems are through the roof. Cape Townians are still growing veggies contrary to Ivo's claims. Only we are doing it with the rainwater from a few weeks ago. We are still showering. Only now the water we showered with yesterday is flushing our loos today.
That is the part with no infrastructural monopoly. Where actual market competition can drive cost reduction and innovation. And it's already doing it.

The final phase of any technology is where it becomes feasible for entrepreneurs to sell it to consumers. First it's giant projects if government. Then giant Corporations selling mostly too government. You can't get to consumer models without those steps. Computers took 40 years to get TBC.