You don’t get it. You’re very naive and inexperienced.
OF COURSE valuable salts and minerals can be recovered from brine.
BUT for every cubic yard of fresh water recovered there is about as much brine to contend with and the treatment of brine takes MUCH longer than the time to produce fresh water. So where does one put all the brine? GET IT NOW? Huge pools of brine are backed up while producing fresh water and the brine volume becomes unmanageable!
You’re sufficiently passionate about the matter for me to believe that either you’ve had your nose rubbed in brine problem or you have an interest in the brine problem not being solved.
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Which is it?
As well, clearly you didn’t read the article I wrote five years ago which shows the academic and entrepreneurial work being done on the problem of converting brine from a cost center to a profit center.
(And yes yes you’re right that its not there yet. But the problem of converting brine waste from a cost center to a profit center is far from insurmountable.)
Read this piece I wrote on where the desal industry was at on the matter of brine reuse back in 2012.
http://www.rdwaterpower.com/carbon-sequestration-and-desalination/watereuse-foudation-symposium/