wealth? Would they have made less money if the current rules had been in place in the past? Is there any evidence of this?

ADs and some other administrators connected to athletics have definitely benefitted from collegiate athletics being a big deal, no question about that. Their jobs wouldn't exist if there were no college athletics. But I think it's a different point to claim that they enriched themselves at the athletes' expense — I would need to see some data to support this. For example, data suggesting that their salaries would have been significantly lower had the current rules been in place in the past.