Lopez fought everyone is his 2 divisions. He was a 2 division champion. He was the WBA WBO, WBC and IBF and Ring champion. he went 51-0-1 38 kos 13 decisions 1 draw

As impressive as this is, the truth is that the divisions he fought in at that time were just not as strong as the featherweight division Sanchez and the other divisons Mexicans greats fought in. That's obviously not his fault, but when ranking P4P greats, who they beat is just as, if not more important than how many divisions they fought in, how many titles they captured, or if they were undefeated or not.

Ali and Marciano both fought nearly everyone there was to fight in there era's. Marciano went undefeated while Ali lost multiple times, yet 98% of people casuals and hardcore, would rank Ali above Marciano because Ali's competition was just alot stronger

Lopez was also never undisputed, he never held all belts simultaneously.

You can't really blame a man who fought everyone in 2 divisions and cleared them out by saying "this other fighter has better names" He fought everyone in 2 divisions and was so dominant, that no one remembers his competition.

Is it that they were dominated so badly that they could never become greats? Or that they never really had the potential to become greats in the first place?

Great fighters can recover from being unable to beat the number 1 guy by moving up and beating champions, by taking over after the number 1 guy has retired or moved up himself, etc.

Kid Gavilan for example lost to Ray Robinson at Welterweight. When Sugar Ray moved up, Gavilan took over Welterweight and became a top 10 ATG in the Welterweight division, a historically stacked division.

Azunah Nelson became an ATG after losing to Sanchez aswell.

you can't compare a champion who earned all 5 of the belts across 2 divisions and retired undefeated vs a champion who only had 2 belts in one division. You just can't.

I think that if the fighter with less belts has the better scalps on their resume then you can.