Google has turned into a cesspool. Half the time I find myself having to do ridiculous search contortions to get somewhat useful results - appending site: .edu or .gov to search strings, searching by time periods to eliminate new "articles" that have been SEOed to the hilt, or taking out yelp and other chronic abusers that hijack local business results.
Yes, they can. They should simply stop measuring only positives, and start measuring negatives - e.g. people that press the back button of their browser, or click the second, third, fourth result afterwards...which should hint the ML classifiers that the first result was total crap in the first place.
But I guess this is exactly what happens if you have a business model where leads to sites where you provide ads give you a weird ethics, as your company profits from those scammers more than from legit websites.
From an ML point of view google's search results are the perfect example of overfitting. Kinda ironic that they lead the data science research field and don't realize this in their own product, but teach this flaw everywhere.
Take a look sometime at the wealth of data google serp sends back about your interactions with it
They ought to see humongous bounce rates with those fake SEOd pages. Normally, that would suggest shit tier quality and black-hat SEO, which is in theory punishable. Yet, they throw that data away and still rank those sites higher up.
You mean to say that no one at Google has even heard of "external SEO", which is nothing more than fancy way of saying link farming? They do know, this is punishable according to their own rules, yet it works, because either they cannot fix it or do not care to.