I don't believe for a second that Google's algorithms are unable to identify and remove content marketing blogspam from the results. It must be profitable somehow for the majority of search results to be utterly useless.
Easy for me to believe. They have to use some formula, and as soon as they change it, well, there's a massive industry dedicated to getting around it. If their algorithm is just "filter out what's useless", that's AGI.
Personally, I swapped to DuckDuckGo in 2019 and have been consistently happier but Bing or whatnot is probably equally valid at this point.
I actually switched to DDG cold-turkey and didn't use !g at all. Until I couldn't solve some problem and someone in my team said "it's the first result on google", I felt pretty stupid then. Since then I've given up and just automatically stick !g whenever I'm searching anything programming related.
Full text search isn't, but ranking the results is - and more importantly there is no objectively best ranking.
[0] When I search "postgres array_agg" on DDG - something I actually had to search for today - the Postgres documentation is the 6th hit (not even visible without scrolling down!), preceded by crap like https://archive.is/7JeSe. On Google it's the 2nd hit, also preceded by what seems like SEO spam.
In this case, DDG happens to have a bang shortcut for postgres which takes you directly to the search results on the PostgreSQL site if you query !postgres array_agg.
There's a surprisingly large number of these which end up making it more useful than the generic web search results page overall.
I doubt a million is going to make a dent in it. Content marketers are automatically generating this stuff, and Google has billions of users, many of which will occasionally invent a novel query.
Old-school useful content is rarely monetized, just someone sharing their passion for something. Occasional affiliate link, with the obligatory apologetic "hey web servers cost money, so I included some affiliate links here!"
The uselessness is just a side effect of Google directing you toward paying customers.
The reason Google keeps those results near the top is because it drives up the cost of AdSense, since multiple competitors are fighting for the first page of organic results with those tactics, and AdSense is a way to "cut the line".
The result for users is that the first page of most result pages is littered with advertisement, either via real AdSense or with those inane marketing blog posts.