Companies were paying far higher than AD agencies were worth, but at the end of the day if one always plays with funny money (fiat), can't you always buy out industries that may suit ones agenda?
A normal investor would likely stay away, because it..
I think it was somewhere between the 1960's and 1980's that there was a boom in mergers and leveraged buy outs in the advertising industry. David Ogilvy speaks about it in one of his books.
In my mind, just like MSM, advertising is well controlled too.
Have you seen "Master Class" advertisements on YouTube?
You know that they are making cover for something when they have Paul Krugman as an economist, Bob Iger from Disney, Natalie Portman, Neil deGrasse Tyson, and Serena Williams.