You dont think Kendrick has an advantage dominating a weaker era?
Being an outlier is just the byproduct, and the weaker era is not within his control.
The game changed and lyrical ability/technical skill/MC integrity is no longer the priority. Labels watered it down, but social media and fan choice supercharged the image/lifestyle of rap completely cannibalizing the craft of rapping.
If anything Kendrick should be seen as the last of a dead breed, which would help folks understand that he'd be just fine if he was born in 72 instead of 87. He's a student of the game, a master at artistic narrative and picture painting, and elite album curator.
Not real life but this is like assuming Luke Skywalker couldn't compare to old Jedi/Sith if he was born in that era.
To use real life, if Ice Cube is considered an elite rapper and GOAT contender by many/most, there's no reason to believe Kendrick couldn't deal with the 90s.