My perspective is a little different. I come at this from two angles. One, I think he's fluffing things up to sell books. Another of his scams. Why do I say this? Because he talks about the pre-Jerry Maguire days as an era of agent/hustlers.
Well, I worked at ProServ back in the 1980s, a huge Washington, DC based sports agency that specialized in tennis, but also had guys like David Falk, Bill Strickland, and even Andy Brandt, who was a young agent at the time. I was in their media department. The clients were incredibly well known--Michael Jordan among them. I worked hard and only left the agency when I decided to take my career another route (and after the agency offered to pay for my law school degree). The point is, even during the 70s you had a bunch of well polished and professional agents. The offices were plush, thoroughly corporate. It wasn't skeezy at all. I'm pointing this out only because there's a right way to do it and remain very successful at the same time.
That being said, I don't doubt that agents and boosters are shoveling cash to players.
As someone employed by universities now, I've come to the conclusion that college sports needs to be ended. We should go to minor leagues. Sports are extracting way too much from schools and have become a monumental headache for universities. I predict it's going to happen for the vast majority of schools regardless, but it would be better if the NBA and NFL just got on with the process and developed their own minor league.