Wayne has had a great career but it's more cause of over saturation in the last 5 years, from 2006-Present, Wayne just flooded the market. His early career was riding the coat tails of Juvi and the Hot Boys, he never stood out at any point during the early years. I agree, Carter 1 was his coming out party as establishing himself as his own artist and he never looked back. He is one of the hardest working guys in Hip Hop. He will drop a verse at any time, on anyone's song, anywhere. But when you look at this albums sales, they aren't as great as some of the best. DMX, NaS and plenty more have sold more albums than him. He also does not have a universally accepted Classic album. When people say DMX, you say "It's dark and hell is hot", when people say NaS, they say "ILLmatic". With Wayne there is no real consenses Some say "Carter 1 or 2" but it's not universal. So the fact he came up to bat 9 times and couldn't make a sure fire Classic says a lot.
Now Single wise, he's a monster, he's had over 80 Hot 100 entrees. But when you've done over 300 Collaborations, it should be expected. Wayne has a lot of quantity but not much quality. A lot of artist don't do as many callabos as Wayne does. As for him never falling off, he already has, he won't move the units he had on C3 again, C4 went double but his 2 previous albums (Rebirth and I am not a human being) didn't do that great. Say he was in jail, say it was experimental, the fact is Wayne's fanbase didn't come out in full force to support those albums. What happens next we will see. What I will say, Wayne does deserve credit for basically being the 1st child emcee to transition to adulthood. Drake and Nicki are great additions to Cash Money's legacy and they did have a great run, but all run's must come to an end. They time is coming, sales are dropping from the label. Drake won't outsell "Thank Me Later" and Nicki probably won't outsell "Pink Friday" the same way Wayne didn't outsell "C3" with 3 albums trying to do it. Everyone falls off at some point, even Jay had a few down years.