DMARC isn't really that big of an issue to wrestle with, and I don't see how it gives anybody influence or power.
Spammers however, they have an economic incentive to have experts set up SPF, DMARC and all the other crap to appear legitimate.
https://workaround.org/ispmail-trixie/anti-spoofing-dkim-spf...
We do have a _tremendous_ amount of spam fail these checks, as well as a few legitimate organizations.... Some of our peer companies have sent out notices that they will bounce anything that fail these checks in the coming years, and we're probably going to to do the same before too long.
It's trivially easy, and absolutely valuable