Your name is invoked because you have the most inside understanding here, even though it is sometimes difficult to parcel out how you explain it. How does cost per thousand tie back to the cost per post cited in the initial post (by me in this thread)? For example, is Ulysses Jr's roughly $14,000 cost per post somehow a multiple or derivative of an industry guideline as you mention right above? Cost per thousands of WHATS? And how are those WHATS measured? Your point about the effectiveness of influencer campaigs is easy to understand. You basically are saying you just measure before and after sales. And your point is clear as to why you cannot simply do 100 posts to up your income. But the ways in which you calculate how to pay the influencers seems much more esoteric and probably not at all understood by the general public (unless they are maybe an influencer or corporate marketer themselves).
An influencer's rate is whatever they choose to accept. Not all are holding out for the top dollar they might be able to get.
The article in the opening post is using a formula of roughly $2.50 per 1000 followers to come up with the price per post. So, if they were to list someone with 100,000 followers, for example, they claim the price per post is approximately $250. They likely don't have any direct knowledge of what these people actually charge or make and that formulation isn't how real world negotiations take place. Currently, the formula is closer to $1 per 1000 followers, but even then there are other things to take into account. Does influencer make good content, is audience responsive, is audience a desirable customer base, where is most of audience located, etc? A content provider focused on high end fashion can charge much more than $1 per 1000. A college student who had one viral post maybe wouldn't be able to charge even that.