I’m not sure what their motivation was, beyond there being a whole lot of people writing mainly opinion and newsy color articles with a quick turnaround. These weren’t really in-depth articles, so I suppose that’s one reason the rates were low. Some feature articles (picked off the assignment desk or by assignment) could pay around $5–20 but invariably we had to give up all rights to those stories so Yahoo could farm them out to syndicating outfits if they chose. In the end, I found it paid better to write ad libitum and gather payment solely on views.
It sounds like your writing was much more research intensive than what I did, so that’s probably why it paid better. I do hope Medium goes more for the in-depth, well-paid researched stuff rather than the pay by view free-for-all that Yahoo Contributor Network could be.