I never knew so many people thought Luke was perfect by the final scene of ROTJ and he’d be the exact same person 30-some years later.
Obviously when you decide not to turn to the dark side, that makes you a perfect person. And once you’re a perfect person, you’re pretty much set there for life.
Seriously though, people are expecting things from Luke based on who he was in ROTJ that shouldn’t necessarily hold true for the character some 30 years later. And honestly, I have a lot of problems with how Luke is portrayed in ROTJ anyway.