Whether it's due to a quite stacked division or a lack of discipline.
For Example:
Luis Ramón "Yori Boy" Campas

He built a record of 56-0 with 50 knockout wins by the time the IBF had him ranked as their number one world title challenger.
Campas also beat former world champion Jorge Vaca by a knockout in round two at Tijuana before receiving his first world title fight on September 17 of 1994 against Félix Trinidad for the IBF welterweight title as part of a Pay Per View undercard that featured Julio César Chávez's rematch against Meldrick Taylor for the WBC light welterweight title. Campas, who had been considered by many Mexicans to be the next Chávez, dropped Trinidad in round two, but he lost by a fourth-round technical knockout for his first professional defeat in 57 bouts.
Campas came back with seven straight wins, including one that gave him the WBO's regional NABO welterweight title, when he knocked out former world champion Genaro Leon in three rounds on August 7, 1995. On September 6, 1996, he was given a second world title try, against José Luis Lopez, for the WBO welterweight title, in Los Angeles, California. Campas lost by knockout in round six.
Campas then decided to campaign in the light middleweight division, beating Fidel Avendano by a knockout in round two in his first fight there. Campas had four straight wins before challenging for a world title again, this time against IBF light middleweight champion Raul Marquez. On December 6, 1997, in Atlantic City, New Jersey, Campas became the world champion by knocking out Marquez in round eight.
He defended his title three times, beating Anthony Stephens by a knockout in three at Ledyard, Connecticut; Pedro Ortega by a technical knockout in eleven at Tijuana; and former Trinidad opponent Larry Barnes by a knockout in three in Las Vegas. On December 12, 1998, however, he lost the title after retiring in his corner in the seventh round against Fernando Vargas in Las Vegas.
He has retired in August 2023 at 51 years old. With a record of 108 Wins 17 Lossses 3 Draws, 83 wins via the way of knockout.

Video by haNZAgod:
Also want to mention Yaqui Lopez and Jose Luis Lopez later on.
For Example:
Luis Ramón "Yori Boy" Campas

He built a record of 56-0 with 50 knockout wins by the time the IBF had him ranked as their number one world title challenger.
Campas also beat former world champion Jorge Vaca by a knockout in round two at Tijuana before receiving his first world title fight on September 17 of 1994 against Félix Trinidad for the IBF welterweight title as part of a Pay Per View undercard that featured Julio César Chávez's rematch against Meldrick Taylor for the WBC light welterweight title. Campas, who had been considered by many Mexicans to be the next Chávez, dropped Trinidad in round two, but he lost by a fourth-round technical knockout for his first professional defeat in 57 bouts.
Campas came back with seven straight wins, including one that gave him the WBO's regional NABO welterweight title, when he knocked out former world champion Genaro Leon in three rounds on August 7, 1995. On September 6, 1996, he was given a second world title try, against José Luis Lopez, for the WBO welterweight title, in Los Angeles, California. Campas lost by knockout in round six.
Campas then decided to campaign in the light middleweight division, beating Fidel Avendano by a knockout in round two in his first fight there. Campas had four straight wins before challenging for a world title again, this time against IBF light middleweight champion Raul Marquez. On December 6, 1997, in Atlantic City, New Jersey, Campas became the world champion by knocking out Marquez in round eight.
He defended his title three times, beating Anthony Stephens by a knockout in three at Ledyard, Connecticut; Pedro Ortega by a technical knockout in eleven at Tijuana; and former Trinidad opponent Larry Barnes by a knockout in three in Las Vegas. On December 12, 1998, however, he lost the title after retiring in his corner in the seventh round against Fernando Vargas in Las Vegas.
He has retired in August 2023 at 51 years old. With a record of 108 Wins 17 Lossses 3 Draws, 83 wins via the way of knockout.

Video by haNZAgod:
Also want to mention Yaqui Lopez and Jose Luis Lopez later on.
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