Yeah, you're forgetting that Hagler did. Hagler, by all standards wasn't even what you'd call a killer puncher, but he did the job on Hearns. I'd say that the big right hand Monzon finished Nino with would have done the same to Hearns. You think that if Barkley could do it, and James Kinchen could deck him, etc., that Monzon wouldn't either? Hearns wasn't durable or tough enough to withstand the greatest middleweight champion of all time, and that was Monzon.
Hagler did? The fight of the decade was an easy win? Not likely. I'd hardly be taking the Hearns from the Kinchen fight. Monzon wasn't no offensive monster who decimated opponents, he wore them down and quite often stopped them later. Just because you consider him the greatest middleweight doesn't mean he's doing to Hearns what you describe. Hearns had great power at middleweight and delivered it far more sharply than Briscoe and co. It's very concievable Hearns could put Monzon on his arse at some point.
You're looking at two very different tacticle approaches, Hagler knew he wanted to rush Tommy,forcing him to fight a battle he didn't want to...Hagler wanted to dictate pace, he didn't want Hearns on the outside setting shots up with the jab...So he made it a war. Hagler had built an extreme dislike for Hearns following a cancelation in '82, I believe...The way Hagler came at him, Hearns could not have changed the progression of the fight. He did not have any choice. Monzon would never engage in a firefight like that...He knew in this hypothetical that he would eventually 'get to' Hearns...Doing what he does best, which is methodically breaking people down...Would it be easy? In my opinion....No. Hearns was an excellent boxer. Monzon was an efficient offensive machine, not a devastating puncher at all...but a punishing fighter. Who used his physical tools of height and strength to perfection...His record speaks for itself. But for number 1 in a head to head sense...I'll take Robinson over Monzon
Monzon loses his normal advantage in height and reach and power, but I think his toughness,tecnique and stamina and late power would be a problem for Hearns, Monzon was the most durable of the 2, Hearns more exsplosive but this is an interesting matchup. IMO Monzon by late stop or close decision
Hearns outboxes the slowfooted Monzon. Even at Monzons fastest he was slower than Hearns. Hagler only got the knockout because he basically bumrushed Hearns the whole fight and took it to war. I could see Hearns on his toes outjabbing Monzon.