Almost any champion from 10 years ago would lose to current champions, precisely because those former talents forced the sport to evolve. That doesn't mean fighters from the past are worse. You have to measure each fighter according to what they accomplished in their peak and how they influenced new generations. Max and McGregor would probably crush WEC Aldo, but planet Earth just couldn't offer something better than Aldo back then. Aldo had to set the limits before Max and McGregor could learn and grow beyond it.