I didn't really take that into consideration. Then it's Johnson, although indeed his style would put tons of people asleep and would people say "the heavyweight division is in a terrible state".
I think that Greb would not only be a boxer but also a UFC fighter today. He made a lot of money fighting outside the ring.
Marciano repeats his feat and wins the unify heavyweight title. And retires with a perfect record of 49-0. With 49 knockouts.
Marciano. Italian- Americans are good to put on the market in the USA, and with his mixture of punching power, chin, stamina, pace and his bone structure he would have a lot of succes at HW...
Something else to consider: The guys you mentioned defined what a "great fighter" should be for future generations. If they were born now, they would never have been able to shape public perception of what an ideal fighter should be like. If it wasn't for these guys, we might prefer completely different types of fighters. For instance, take Marciano. At first glance, he seems to fit the stereotype of a bankable fighter. He's a tough, determined Italian-American slugger/brawler who throws punches in bunches. But that type of fighter (slugging Italian-American brawler) is popular partially BECAUSE of Marciano. Without him, we might instead have a preference for the OTHER successful type of fighters in his era--slick "old school" defensive geniuses like Moore, Walcott, and Charles. We might appreciate fighters like Toney more and fighters like Mesi less. Johnson is similar. In part, the swaggering, trash-talking braggadocio of some modern fighters owes a lot to Jack Johnson. And Tyson certainly benefited from the love of whirlwind knockout artists that Dempsey created in boxing culture as early as the 20's. So it goes...
Sombody who could be huge. Max Schmeling Imagine the gates that a German born world champion could bring in Germany today. Incidentaly Schmeling Neusel broke all boxoffice records for a European fight. I guess what goes arond comes around.
Jack Johnson - Would be booed like John Ruiz was booed for excessive clinching, and fighting soft touches while champion. However, I do think he would be interesting at the press conferences! Harry Greb - Would be worth his weight in gold. Sugar Ray Robinson - Would be worth his weight in gold. Rocky Marciano - If Rocky was in the cruiser weight division, he would not make that much money. As a heavyweight champion, I think would make about as much per fight as say, Lewis or Holyfield. Having said that, we are in a politically fragmented era of boxing. All of the above fighters would be alphabet champions today, not lineal champions. This means fights with the other 3 champions who would be viewed as their chief completion might not happen.
SRR for me. His marketability, charisma, business sense, longevity and unbelievable talent is going to bring him forth in the modern era. His talent IMO would let him clean up from 147 to 160 with a decent chance of success 175 and 168 as well.
Wouldn't worry SRR. Given the schedules of today his longevity would be frightening barring unseen circs.
Not to mention faster cut/swelling stoppages and more clinching allowed by refs. Although I believe Marciano would absolutely be champion in the modern era whether he chose to fight at cruiserweight or heavyweight, all of those things would certainly weigh down on his success- he was really much better-suited for the era he actually fought in.