If todays fights were 45 rounders or fights to the finish.

You'd get asleep before it's finished because the fighters would injure their hands at some point and whole rounds would be spent without a single punch thrown or landed by either.

 

Thankfully we have very little footage of them clothed like that

But really, fights would become boring past certain number of rounds. Usually they had their hands all used up and puffed at some point, and then it became a walking match, rather than boxing. There are very few exceptions in history where there was plenty of action the whole distance.

 

then jack johnson , sulivan and every old school fighter would own any modern fighter, all that they would need is survive the first 15 rounds, and then they would make anyone their bitches

 

There would be a greater emphasis on offense and less point fighting. If you couldn't knock a guy out in 15 you more than likely wouldn't get into the ring.

On the other hand, I've heard it said that knockouts come easier the longer the fight lasts, and so defensive wizards like Whitaker or Mayweather would grow stronger as their opponents weakened and drown them in the deep water. So instead of a 36% knockout rate, Pernell might have more like a 76% knockout rate. It's possible.

However, I am reminded of Sugar Ray Robinson collapsing in the heat against Joey Maxim. In the later rounds Robinson continues to dance while Joey conserves energy and is practically immobile. Ray, well ahead on points, drops down exhausted and Maxim gets a knockout. The extra rounds would put a limit on a fighters mobility. Instead of skipping around the ring like Muhammad Ali, you'd have to stand in front of your opponent and make him miss like James Toney, Bernard Hopkins, George Benton, and Archie Moore. More shoulder rolls and Winky Wright defensive shells.

Guys with stamina and chins like George Chuvalo and Jake Lamotta would definitely have an advantage. Guys with weak hands like Maxie Roosenbloom, Nicolino Locche, Tommy Loughran, and Willie Pastrano probably wouldn't amount to much.

You also wouldn't see a lot of moving up in weight. A lot of the skilled smaller guys would move up knowing that their skill would protect them and lead them to a point victory over ten or fifteen. They'd usually pick soft punchers knowing that they could last the distance with them. But no way could they last 45 rounds with some of the mismatches in size. Around round 15 they'd slow down and get clipped in 20 by the bigger stronger guy.

 

Jack Johnson of the Jeffries fight versus Jess Willard in Havana might have been very interesting indeed.

If Jack was to win in that torrid climate, it would have had to be by 45 round decision against a durable puncher with immense strength and stamina who had killed a man.

No question Li' Artha' would have had an insurmountable lead by the halfway point, but could he have survived to the final bell?

Many were postulating in 1982 that if all bouts were scheduled for 45 rounds that Tex Cobb might never have been beaten. Against Holmes, he did in fact make his move during the championship rounds, but Larry stepped up his own pace accordingly. Tex was not a bleeder, despite his own claims of being susceptible to cuts by virtue of being white. [This was a bull**** bill of goods he was trying to sell. Bonavena wasn't a bleeder either, or Arguello, while Napoles was a notorious bleeder, and to a lesser extent, Saad Muhammad. Black fighters commonly are not thought of as bleeders in part because the color contrast it not so evident when they do bleed, but there certainly have been darker skinned fighters who did cut as easily as their Caucasian counterparts are stereotyped vulnerable to.] For Cobb. not being a bleeder could be as crucial as his natural size, strength, stamina, and punch resistance to both head and body.

Benny Leonard and Roberto Duran would have had a good challenge dealing with the Old Master in Goldfield. At his best, Joe Gans clearly had no issue with going the 45 round distance in the desert head of mid summer, and was actually boxing for the final bell when Nelson waved the white flag by purposely fouling him in a flagrant act of concession.

Gans, not Greb or Robinson, would likely be acclaimed the P4P GOAT today, although the advent of triathlons and ultra marathons might be producing many of today's top boxers among modern challenger's to the all time status of Gans.