[criley2]

My conspiracy theory is that google intentionally has degraded the ability of spam to be detected.

Why? Google Inbox did it absolutely perfectly. They wrapped up every email, from every major source, into nearly perfect bundles.

You could receive hundreds of unsolicited ("sOlIcItEd") marketing emails a.k.a. spam and Inbox would perfectly roll them into one bundle with a 1 swipe gesture to archive.

Then they killed Inbox and Gmail has functionally no ability to collate spam into a bundle and hide it.

That's intentional. Email marketing is huge, and google has a massive vested interest in ensuring that gmail users can see advertisements.