Not all great athletes are great performers. In their specific sport? Yes, they’ll be great performers! But not all great athletes have the ability, charisma, or capability to be entertaining and do that in a pro wrestling venue, and entertaining and acting are key to wrestling. You allow people to show if they can pair elite athletic performance while performing as an entertainer. If they can’t or don’t improve, it is what it is.
Obviously, WWE/TKO didn’t think he’d turn into anything that they could use creatively or to help financially. So it goes.