Spammers are better at SPF, DKIM, and DMARC than everyone else

For me, as someone with their own mail server, these technologies mostly serve to inform me that Russian IP addresses are still trying to send email in the name of my domain for some stupid reason.

It makes sense that people whose business is sending email know how to set up email correctly. I'm mostly surprised at how many legitimate sysadmins struggle with getting the basics correct. Surely those dozens of DMARC emails you get that your sendgrid email has been refused because of a bad SPF signature should set in motion some kind of plan to ask if maybe marketing is using them legitimately?

Automated signatures are of limited value but I rarely see rejections based on SPF and DKIM that are a mistake. Things are probably worse for big organizations but as a small email server, technical rejections are usually the right call. The only exception is mailing lists, but the dozens of people who still use those can usually figure out how to add an exception for them.

In most organizations there is no point in a sysadmin to spend the effort in understanding how to set it up correctly as Marketing has got more authority on email. Marketing will simply demand changes to the config that they do not understand and there is nothing you can do to stop it as they will have the CEO on their side.

You mean like the time I had a salesperson demanding that we turn off Cloudflare across our entire domain because he'd read some random article somewhere saying we should?

The goal of sales isn't to block upto a 1/3 of world wide traffic. Turning off Cloudfare means more traffic and more sales are not blocked. Did you even read the article or did you dismiss it because it came from 'sales'.