And there is zero short term solution to their water supply problem. None at all.
They will either become nomads or refugees.
First guess ?
You are correct.
It is economically impossible to fix the ancient Qanats.
Israel has bailed out Iran water system out twice.
The Mullahs of Iran an die of thirst as far as I am concerned. But the Iranian people are not like them.
The Greatest Threat Facing Iran: Running Out of Water catastrophe (Seth M. Siegel, Sep 16, 2015)
https://www.tabletmag.com/sections/israel-middle-east/articles/iran-water-crisis
Excerpted from: Let There Be Water: Israel’s Solution for a Water-Starved World. Copyright © 2015 by Seth M. Siegel
How Israel became a water superpower (Dec 1, 2015)
https://www.timesofisrael.com/how-israel-became-a-water-superpower/
There is a lot more to be gained by working with Israel.