It's not efficient. At scale, you'd try to be orders of magnitude more efficient.

This is specifically for portability & low maintenace (not needing to keep swapping/handling filters).

If you're on a boat it should keep you alive, with some modest solar. But most everyday consumers have far larger water needs & trying to generate all that desalinated water via this process is not effective.

Yes there are already giant desalination plants in the Middle East.[1]

[1] https://www.nytimes.com/2019/10/22/climate/desalination-wate...

IIRC California has desalination plants. I remember hearing Catalina has one but only uses it when they absolutely has to.