I believe that Charles, Spinks, Moore, Conn, and Loughran would give him a good fight. Also Holyfield. I would give Evander the best chance, but I think he’d come up short.
Moore and Charles are good shouts, although Dempsey is favorite. But the other two, hell no, Dempsey mops the floor with them, especially with Fitzsimmons. Dempsey would probably beat 10 Fitzsimmons's a night. Mike Tyson would beat 100.
Dempsey was great but saying that he had an iron chin is a stretch. He was stopped in one round by Fireman Jim Flynn and knocked down twice by Firpo including completely out of the ring.
Do you even know that Langford and Dempsey are contemporaries? Are you aware that they faced mutual opponents? It's not old vs new in this case, Langford fought in the same era as Dempsey. Dempsey had a lot of admiration for Langford. Langford faced and beat better competition than Dempsey. Again, Fitzsimmons was arguably the best fighter in the world only 15 years before Dempsey reached world level. In other way, you are clueless again.
I'm curious what leads you to believe he has an iron chin? If your case is his chin would be iron against 175lbers I could believe that maybe. But an Iron chin as a heavyweight? Against ATG athletic huge powerful men in later eras? Carpentier put him on rubber legs average hitting Brennan hurt him badly Flynn knocked him out in 1 round Sharkey landed flush on him, but Sharkey never proved himself a big hitter He never fought by far the biggest puncher of his era, Harry Wills The Firpo fight certainly showcased Dempsey's recuperative abilities, heart and ability to fight hurt, but does it prove he has an excellent chin? He was knocked down 2x, also pushed/punched out of the ring. Tunney won 19 of the 20 rounds in their two fights. Was it that competitive? I've seen the footage slow just like you have
Interesting since Dempsey turned down a fight with Sam Langford in 1917. Wonder why you think Sam has no shot? Sam is one of the greatest two fisted punchers of all time, he had athleticism, speed, reflexes. He was strong and could take a punch.
Holyfield is the better more rounded boxer, but Dempsey had speed and power, and that can balance things out a bit. But I still see Holyfield winning.
Dempsey is a decade younger. It's way more than 15 years. By the time Dempsey reached world class level (say around 1917, 1915 at the earliest), Fitzsimmons was already dead. Fitzsimmons best years were before 1900. His skillset is nowhere near as good as Dempsey's, Dempsey would destroy him.
I’d like to have seen Conn fight Dempsey. That’s a real fight. I’d take Billy to win, plausibly. He’d be who I’d root for.
Which doesn't disprove anything I said. Langford was the best fighter in the world at the time Dempsey started his career. Fitzsimmons died young, that's not an argument. But he was still the best P4P fighter in the early 1900s. That's funny, because most contemporaries would strongly disagree with that statement.