These days I assume that Google does two things at once: place clearly identifiable and directly billable ads, and include "is a known business" in the relevanc

These days I assume that Google does two things at once: place clearly identifiable and directly billable ads, and include "is a known business" in the relevance algorithm blackbox as one of the inputs. One of the many factors and criteria would just happen to be ad spend. There wouldn't be an item "make us more relevant" on the bill, but relevance for a company stopping spending would drop unless some other organic factor happened to compensate. And I'd take it as a given that if that assumption was true, a large majority of Googlers would not have the faintest idea that this is happening and refute any speculations that it might exist without even a trace of insincerity. I'm not even saying this intending a "look how evil Google has become!" implication, I actually think that it would likely be a quality decrease, from the users perspective, if they deliberately left that out. From the user's perspective, "Is a business known to us" is likely a valuable relevance improvement, not a quality decrease. But it shows how scarily dominant Google's position can be.