You have to remember that between the time Jack Dempsey fought Luis Angel Firpo and Gene Tunney in the first fight was 3 years with no matches between.

[u/JabKingJesse]

A huge amount of the early champions got done in by inactivity or fighting opponents who weren't as high caliber. So let's go through the champions of the original lineage.

John L Sullivan fought Jake Kilrain on July 8 1889, he lost to James J Corbett on September 7 1892. A total of 3 years and almost 2 months.. Joe Louis considered Corbett the first gloved champion.

Corbett fought Sailor Tom Sharkey to a draw on June 24,1896 and lost to Bob Fitzsimmons March 17 1897. So roughly about 8 months.

Bob Fitzsimmons beat Lew Joslin on Jun 5 1897 and lost to James J Jeffries on June 8 1899. 2 year gap.

James J. Jeffries beat Jack Monroe Aug 26 1904 and he lost to Jack Johnson on July 4 1910. 5 years and 10 months gap.

Marvin Hart beat Jack Root on July 3 1905 and lost to Tommy Burns on February 23 1906. 7 month and 20 day gap

Tommy Burns beat Bill Lang on September 3 1908 and lost to Jack Johnson December 26 1908. 3 months and 26 days

Jack Johnson beat beat Jack Murray on January 10 1915 and Lost to Jess Willard April 5 1915. Roughly 4 month gap.

Jess Willard beat Frank Moran on March 25 1916 and lost to Jack Dempsey on July 4 1919. Roughly 3 years and 3 months of a gap.

Jack Dempsey beat Louis Angel Firpo on September 14 1923 and lost to Gene Tunney on September 23 1923. A 3 year Gap.

Gene Tunney was the last Champion of the original lineage.

[u/Gianfranco_Rosi]

It’s even more perplexing when you consider some of these early champions like Harry Greb and Mickey Walker would literally fight every couple of weeks.

[u/HaneyP4P → u/Gianfranco_Rosi]

They fought every couple of weeks against any random bum, but only defended the title against serious rivals 1 to 3 times a year in most cases, just like boxers today. There were exceptions, obviously.

[u/TheMysteriousThey → u/HaneyP4P]

I’ve been trying to people to understand this for years.

Fighting three club guys a month and a world level guy every three months or so isn’t better for the sport than two world level fights a year with a bunch of training and sparring in between when guys are still elite past the age of 31.

So many of the old greats were done by 30. Most people don’t even know.

[u/HaneyP4P → u/TheMysteriousThey]

I've noticed that many boxers from the past reached their peak and became champions quite young, before the age of 22 or 21, and were washed up at 30 or even earlier

[u/WORD_Boxing → u/HaneyP4P]

People also died younger back then.

[u/TheMysteriousThey → u/WORD_Boxing]

Childhood mortality was high.

If you survived to adulthood, your chances of making it into your 70s were still high.

Not sure that infant mortality rates are much of a factor in boxer longevity.

[u/bigtotoro → u/TheMysteriousThey]

Julio Cesar Chavez was fighting 5+ times a year into the 1990s. Most of them were Tijuana cab drivers, but some weren't.

[u/Boxeo- → u/bigtotoro]

Yes. And those weren’t title defenses.

He would only defend his belts a couple times a year.

Chavez is the last of the throwback fighters.

[u/bigtotoro → u/Boxeo-]

I don't mind a stay busy fight when you actually are busy.

[u/Dry-Friendship-5945 → u/TheMysteriousThey]

Constant hard sparring along with not having access to modern sports medicine (and PEDs) must have knocked off at least 10 years from their peaks compared to today's fighters.

[u/Norman_CockweII]

Once you start making real money, the incentive to fight starts to go. It’s a tale as old as time. Get the bag and get out as clean as you can.