@jahed fair point, Google has a huge part to play too. Not letting users filter out particular sites is ridiculous, and why Kagi is doing so well at the moment. Meanwhile the obsession with trying to ‘second guess’ your search by removing useful tools like quotes, hyphens, etc or finding terms that only have one word is terrible too.
But SEO does play a role as well. Constantly making new pages to rank for terms that you have nothing to say about clogs up the listings.