You can link me studies that are paid and bought for by these companies all day long. Find me one where the guy is not a consultant to the companies themselves.
Obviously not compelling on its own though.
This seems like a relatively small inefficiency in the markets, no? If the margin of error notable in a prediction markets is <10 cents per dollar, that implies that they are pricing events pretty accurately. Especially post publication of this paper, when sophisticated traders could trade away this inefficiency.