Flair in the 80s was a god at wrestling, his 90s saw much of his abilities start to dip and his attitude started to see him give less of a shit every passing year until you could tell he was phoning it in. While his 2000s was not much better, the difference was most of his abilities declined rapidly but he at least found the passion again.
I look at it like this:
70s-80s Flair: Passionate and Peak Ability
90s Flair: Lacking Passion and Abilities are starting to decline
2000s Flair: Newfound Passion but the Abilities have declined severely.