Before I pick at this, I'll clarify that I don't think Google is
useless. It's still perfectly fine for many uses.
> Now it's seven pages of nearly identical listicles, some of which are on bizarre domains like "DougsAutoBodyAndFlowerShop.com", and all of which are festooned with ads, also provided by Google.
> From what I understand of your complaint, sometime in the last 20 years, the Google stopped finding outsider art. I would guess that's due to SEO. And with anything that's known to drive revenue to a business, that sort of thing becomes a target. So people target the Google algorithm to place better. I don't know that there's a solution to that. But I don't think it's because of a change inside Google - more like a change in society.
There has been SEO for all of these years, and the search engines have historically been in an arms race with these efforts to minimize how readily ranking can be gamed. "some of which are on bizarre domains" is the more important part of the complaint. It implies that Google has either stopped playing this game or has started losing the arms race.
I have (for years now) been regularly finding search results where pages that are obviously scraped from a stackexchange network site (and more recently from github or reddit and such) and stuffed full of ads are ranking above the original threads on their canonical sites.
Scammy/bizarre/non-canonical domains outranking canonical sources in search results is putting Google-search users at elevated risk of being phished or infected with malware, so it's not like the stakes are low.
As we've watched this drag on long enough to ~metastasize into the kinds of sentiment you're pushing back against, it's grown hard to imagine explanations that boil down to anything ~better than indifference or negligence (and leaving a lot of oxygen for explanations that involve incompetence, malice, etc.).