The accounting firm PwC (does that still stand for “Price Waterhouse Coopers”?) has done a study <https://www.theregister.co.uk/2020/05/07/ad_tech_fees_sucked/> of the online ad market, to see where all the money is going. Turns out only about half the money spent by advertisers makes it all the way to the publishers, with the rest siphoned off by various intermediaries along the way (not all of them legitimate), and 15% could not be accounted for at all. Much of this trading is now done “programmatically”, between automated systems, rather than by direct agreements between humans. And these systems are more complex (i.e. “having more stages where a percentage cut can be taken”) than they need to be.