>>149251022 (OP)Byrne wanted to keep him on the team so he kept finding ways to make him come off as cool, like showing he had a mysterious past and stuff, or memorable moments like Wolverine rising from the sewers and taking on the Hellfire Club
Claremont (who initially wanted to remove him from the team) started seeing the potential and took it further with stuff like that Wolverine miniseries
So he became this guy with a mysterious past that he can only remember parts of
Then he got an ongoing in the late 80s and Claremont, Larry Hama, etc added more to the mystery
BWS did the Weapon X story