@JS_Harris what you are suggesting is scary, at least to me. I think we all agree that we are just speculating here but I fear that what you are saying may well be true.
First off, when I do searches in my niche, regardless of the website that I find the information that is reported is almost always from the same source, sometimes re-fangled and refined but mostly simply repeated, the information is often wrong, not because the source is wrong but rather the interpretation is wrong. None the less these sites appear to do much better than mine.
I treat the same topic, but I have developed my own extensive data source, at times my site agrees with the "norm" and other times not at all. To the average user that lands on my site, when they see information that conflicts with the "norm", since I have not yet developed recognition or authority, this user probably believes the twelve other sites more than mine. Google probably holds the same opinion and use the approach to arrive at its opinion.
Now let pretend that I am right (I am right! I am always right, but that is another conversation), and the "norm" in a world without Google disagrees with me. In that world I only have to overcome those that disagree, by convincing them otherwise or disproving them in some manner. The key is we all have the same weight, if I am 1 and they are 10 it is 10:1 ratio. But in the Google-verse, the dynamics are different it is not simply 10:1, since Google is taking sides, that is siding with the "norm", I end up invisible, powerless, pushed to the bottom of the serps. User's never hear my arguments, so it's game-over or at least a steep up-hill battle.
I am still skeptical as to whether Google is doing this, but about a year ago they released a paper relating to the topic of being able to answer factual questions and the paper basically explained such an approach, where it searches the web for credible sites with answers to the question at hand and if most sites agree on one answer it assumes that it is right answer. This algo was said to power the knowledge Graph.
Moreover, A few weeks ago I had a conversation on Google+ with John Muller regarding the fact that my svg-graphs did not appear in image search. He suggested that maybe my graph did not appear in search because they did not rank or warrant being in image search. He said take a look at what other in my niche are doing, and do something similar. This was not the cause at all, since my graphs were picked up in image search as soon as I shared them on twitter. The real cause was because they were tagged as <object> and not <img>, whereas on twitter I posted png screen caps. Back to the point, John Muller, suggested if you want to rank do as others do.
This scares me, not because all the work I have done might simply be ignored. My site treats a trivial topic, so I am bothered, but not scared. But innovation stems from a one person's ability to disprove widely held beliefs, and Google has designed a monster robot that will quash any site that disagrees with the norm. To some extent this is probably necessary, because the other extreme is no better. That is, where anybody's point of view is given the same weight regardless as to whether the claim are substantiated or not.
The bottom line is that determining who to trust and who not trust, is challenging even for the smartest humans. Programming a machine to do it is probably close to impossible.
One final philosophical note, it is impossible to prove anything by confirmation, using Karl Popper's analogy of the black swan, you can find as many white swans as you like, but it only takes a single black swan to disprove the statement that all swan are white. Based on what JS_Harris describes, if someone finds the a black swan Google's algos will hide it deep in cyberspace so that others will never see it.