That was disrespectful by Royce. And while yes, Jay is better than Kane, the fact of the matter is he SHOULD be at this point. Jays career is unusual - he was actually trying to get a record deal in Kanes heyday, could not get signed, and hit the streets (I have always said, the best thing to happen to Jay was that he was told no in the late 80's, early 90's). There is video on the net of Jay rapping at the intermission of a Kane concert. Now I would hope Royce understands this - '88/'89 Jay-Z ain't better than '88/'89 Kane! The advantage Jay had was he saw the Kanes, Rakims, G-Raps, and then the next era of the early 90's (Redman, Grand Puba, etc) and then came out in the mid 90's. Now, he has seen a gang of great MC's, and he knows he has to take it to another level. So comparing them is really unfair.
If you are an elite MC, by rule you SHOULD be better than the elite MC's of a previous era. Rap is often compared to sports. I think the dunking is a good example. The fact is Zach Levine and Aaron Gordon are doing significantly better dunks than Jordan, Dominique, and even Vince Carter did. But they should. They've studied those dudes and added new shyt. But you wouldn't say, oh MJ couldn't outdunk a picture of Zach Levine. That just sounds stupid.