These things aren't all true in real life, and on the internet it's even easier to fake all of that.
In the beginning Google went by 'amount of text' (which is why you read everybody's life story on how they had sex next to a magma flow in Hawaii which created the idea of doing burnt ends on a pizza stone), references (remember all those backlinks which would boost your page). Credentials are a lot harder to track. There is no API at my school where you can put in my name and see my credentials (and all you'd see is 'we got governments subsidies for this person, which is why we let him pass').
And all of this worked at the start. Knowledgeable people naturally had references on the web, as only knowledgeable people were on the web.
Now we literally have people writing text purely to make it look like their website has more content on them, even if it is remotely related to what they serve.
Great example, even posted here: https://news.ycombinator.com/item?id=36740400
Or any coding problem where you end up on logrocket / some partitioning app / some generated website with which has an 'answer' for KB0000000 -> KB9999999...