alt Hacker NewsDMARC, just like SPF before it, solves nothing. The spammers adapt. And unlike SPF, DMARC has an enormous technology surface area. Its failure modes are legion, and each one is tedious to run down to resolution. Which just returns you to something which never pays the rent anyway.
One awesome thing that SPF/DKIM/DMARC did... Now that spammers have "adapted", it means they can't say their email is from @mybank.com, or @microsoft.com, or @facebook.com, etc!