Considerably bigger, much faster Dempsey is one of the most important fighters ever, completely changed the game... But he was a prototype. He would have been obsolete against a good fighter from 10 years later... Now, Haye is flawed and not very good, I think he's flashy cannon fodder in a better era, but he still possesses enough speed, size and athleticism that he would've romped through the heavyweights of Dempsey's era (19teens to mid 20s) with ease
If, and its a big if, Dempsey could stay in the fight, especially at the 200lb limit, he could get Haye to gas.
No chance of that. Dempsey was revolutionary in that he was the first to realize that you can defend yourself while attacking. It was a brilliant idea and renewed boxing forever after, but Dempsey himself did it rather poorly. He got hit, and up close he wasn't nearly as effective as historians make him sound. For years I read the stories about how Jack Dempsey fought Tom Gibbons and chased him around the ring but Gibbons went the distance with his movement. What actually happened was that they stood shoulder to shoulder and Dempsey had the upper hand because he was way bigger but couldn't hurt the dwarf in front of him nor really even penetrate his defense. Even if Haye stood in one place, Dempsey wouldn't hurt him. In reality, Haye wins in the first
