I am not trying to be insulting but you are not an aficionado of the sport if you do not understand the quality of his resume. Your failure to recognize the many names he fought from MW to HW does not mean they are not there.
Or you are trolling?
Let's look at just the guys that were contender or champ status (and not the rest of his resume):
Tiger Flowers
Jimmy Delaney
Maxie Rosenbloom
Mickey Walker
Gene Tunney
Tommy Loughran
Jimmy Slattery
Kid Norfolk
Tommy Gibbons
Gunboat Smith
Mike McTigue
Battling Levinsky
Bill Brennan
Mike Gibbons
Billy Miske
Willie Meehan
Jack Dillon
Jack Blackburn
Jesus Christ, the more I read his resume, the more impressed I am he doesn't have more losses. He fought some of them five times, four times, three times. It's insane how often he routinely rematched top 5 guys or contenders (in an era with ONE belt) in three different weight classes.
If you factor in the number of times he fought each of the above guys, he has as many or more fights than the entire resume of many pros of today, AND his record is better. Nobody, and I mean nobody walks through that list undefeated in boxing. Ever.
He has literally ZERO ducks on his resume in two weight classes (against fighters that would become champs or contenders at HW).
Cans?
Are you half-blind?
Oh, no, sorry, Harry Greb was blind in ONE EYE and still fought killers from the second Norfolk fight in 1921 to his death in '26. He only lost to Tunney 3x, Loughran 1x, Norfolk 1x, and Flowers 2x (both which many saw as wins for him) in that time. That makes him with 90 fights and only 7 losses when he was half blind. Those losses during the half blind years of his life are against guys that campaigned at heavyweight and Greb was a natural middleweight and he BEAT those guys on other nights in the same time period.
All he fought was cans? Read a book.