It's not Google's fault this time.
The problem is that Blogspam is now a (legitimate) industry much bigger than Google can manage.
Google Search became a playground for marketing firms to dump content made by low-paid freelancers with algorithmically chosen keywords, links and headers. It's SEO on large scale. Everything is monitored via analytics and automatically posted to Wordpress. Every time Google tweaks its algorithm to catch it, they're able to A-B test and then change thousands of texts all at once.
Personal blogs can't even dream about competing with that.
In fact, those companies are actively competing with personal blogs by themselves: via tools like SEMRush and social media monitoring, they know which blogs are trending and use their tools to produce copycat content re-written by freelancers and powered by their SEO machine.
I know a startup that is churning 10 thousand blogposts per day on clients blogs, each costing from 2 to 5 dollars for a freelancer to write according to algorithmically defined parameters.
Just wait until they get posts written via OpenAI-style machine learning: the quality will be even lower.
Not only that: there's no need for black hat SEO anymore. Blogposts from random clients have links to others clients blogs, and it is algorithmically generated in order to maximize views and satisfy Google's algorithm. They have a gigantic pool of seemingly unconnected blogs to link to, so why not use it.
The irony is that companies buy this kind of blogspam to skip paying AdSense. Why pay when you can get organic search results? So not only they're damaging the usefulness of the SERP, they're directly eating Google's bottom line. These blogs also have ZERO paid advertising inside them, since they're advertising themselves.
That's the reason Bing, DuckDuckGo and Yandex still have "old web" results.
That puts Google in a very difficult position and IMO they're not wrong to fight it.