First off, people run different races. You can't compare JayZ to a Ghostface. JayZ became a rapper to make money and to create a brand. He was never in it for art's sake. He was never in it to further the culture. Jay started rapping because he saw dollar signs. Also, JayZ isn't more relevant than any of his peers, he's simply more commercial. Relevant is completely subjective to the listener. For me, JayZ lost all relevancy way back when.
To answer the question...
-He was more business-minded, while a lot of his peers were all about the culture and art of rap.
-He had no problem stabbing niggas in the back or in other words, he didn't follow the street code that a lot of other people did aka he kept it business.
-He had no problem consciously ridding the game of his competition.
-Everything was calculated. He had a plan.
-He ran a different race. He was all about hits and album sales etc.
-He embraced and wanted fame. This is huge, because most people don't want to get too big. That shit is way more of a curse than a nightmare. However, if you embrace it, a lot of good things can come of it.