I don't think Pac Man cares about belts - why would he 'defend' an international title about seven times! The belt is secondary to the guys in the middle - the way boxing is these days means this is commonplace.
How so? Winning two belts isn't even full unification much less Lineal. The 3 different ways people contend that a lineal champion can be re-established after it has been vacated or broken are as follows (to my knowledge) 1. WBA-WBC Unification. (I doubt this is accurate since it has been re-established without this. But it is arguable since they are the 2 oldest belts) 2. WBA-WBC-IBF Unification. (WBO may be apart of it NOW, depending on who the champion is. But as recently as last year it was unnecessary to be considered undisputed) 3. A #1 vs #2 matchup between the 2 recognized top fighters in the division. (Usually taken care of by the 2nd equation, but not always. And they have fought before without belts to create lineage as well, so this may be the ACTUAL way it is done of the 3, with the 2nd one being a byproduct of this one. Problem is, who decides who the top 2 are?) Point is, none of those 3 situations was present when Pacquiao faced Sanchez. Neither was considered #1 or #2 (Pacquiao was rated #1 by Ring after the fight with Sanchez, behind Ayala who was the Ring champion). And it wasn't for total unification. So even if he had won, he wouldn't have been lineal.
My P4P list places more emphasis on perceived ability and H2H. My ATG list is based mostly on accomplishments/resume. All of it is factored in on both lists, but certain things are emphasized more on each.
most of the time, ring re-establishes lineal b.c of the #1 v #2 matchup that is required for it. Except for some notable exceptions like Vitali and Hopkins at light heavy.