DKIM, SPF, and DMARC are old hat and implemented by anyone serious for years. What's buried in this article is the required https://datatracker.ietf.org/doc/html/rfc8058 support for one-click unsubscribe posts. I don't see many messages in my inbox yet with that.
That's very odd to me. Where are you located? I'm in the United States and virtually all my newsletter/marketing emails have one-click unsubscribe these days. The only ones which don't are from foreign companies, e.g. I bought a day planner from Hobonichi and found they put their unsubscribe behind a login, to my irritation.
I’d say somewhere around half of the marking emails I receive in the USA have one-click unsubscribe. It’s still very common to have unsubscribe links that require you to enter your email address and then select that you actually want to unsubscribe from everything, etc. And some of them still require logins, although those are getting rarer. Not sure if it’s actually a loophole, but one of the dark patterns I’m seeing often is one-click unsubscribe generally only unsubscribes you from a very specific type of notification or topic of the mailing list, and you’ll still get other types of emails unless you fully log into your account and go in your email settings and unsubscribe from everything. Not sure exactly how Google and Yahoo treat those, but it feels kind of like marketers found a loophole that seems to work for them.