I can’t read the article due to the pay wall, but this makes sense. If you own the software to buy, the software acting as the intermediary, and the software to sell, you’ll make 3x more than a competitor who only owns one piece.
(I don’t use the products and I’m sure the names have changed, but dv360/dcm, whatever they call their exchange, and dfp)
I’ll leave the morality/legality/etc of as an exercise for the reader.