Man rappers don't just lose it to me
this isn't athletics where the body can be damaged due to wear, tear, and age.
The only thing that changes is the musical climate that these rappers exist in.
Per example: Take lil wayne. He did not lose anything. The answer to Wayne's "Struggles" is simply the fact that when he was hot, the focus in rap music was outlandi*****, cleverly stupid punchlines, with no real structure. The punchlines were hot and wayne was the king of those.
Now? The focus isn't really on punchlines but more on coherent verses, melody, ear pleasing sonics, songwriting, etc. thanks in large part to Cole, Kendrick, Drake, Wale, and others. That pure 100% no coherence punchline rap just doesn't fit with what people deem as hot anymore.