What could of been within the context of the fight isn't relevant. Through Anderson's reign in the UFC he faced 10 fighters based in grappling & he handled all of them until he eventually lost 7 years later .
If we look at the LHW & MW rankings from 2010 for instance we see [From 1st to 5th]:
LHW: Shogun, Lyoto, Rashad, Quinton, Forrest.
MW: Anderson, Sonnen, Shields, Marquardt & Henderson.
The number one ranked fighter has been defeated by two of the top five in the smaller division. Lyoto & Rashad fought SD's against No.5 ranked Henderson. Forrest was defeated by Anderson.
If we go to 2007 [From 1-5]:
LHW:Rampage, Dan Henderson, Wand, Shogun Rua, Chuck Liddell
MW:Anderson Silva, Rich Franklin, Thales Leites, Nate the Great, Yushin Okami
The mediocre fighter 'Franklin' has wins over two of the LHW top 5. Anderson Silva handled Henderson who was [No.2] during this 'weak' period.
There is a difference between perception and fact.
Lyoto beat the man Silva beat to become champ in only his 3rd pro fight, and not only fought above his natural weightclass unlike silva, because of his friend silva, but didn't get an easy titleshot like silva. He effectively "defended his belt" before he became champ, unlike silva who was gifted a titleshot, and then beat the man machida already beat. Because mma is an unorganized "sport", where the bosses and matchmakers make the fights not the ranking of fighters, MMA accomplishments are more preception than fact. And besides all that, if machida beats weidman, he will have accmplishd something that silva hasn't, becoming a 2 division champ.