With the portal and NIL he couldn't (a) pay under the table for better talent and (b) practice his particular brand of authoritarianism on his players.
He saw the handwriting, and got out.
Let me add...although his legacy is impressive, his only naty since 2017 was in the pandemic year, and thus has an asterisk after it. Although they have been in the naty picture ever since 2017, it just hasn't been the same since Clemson dog whipped them in 2018. IMO.