An easier example of the same thing is Han Solo in TFA. Han returns to smuggling? Why? Han didn’t enjoy smuggling, or do it because it was his lifelong dream. He did it to get ahead, to make a buck. Why the heck would he return to a life of crime after having been a war-hero married to a princess/politician? Didn’t Leia and Han have a shared bank account? It’s just absurd. A better alternative would have been that Han was using his old skills to find allies for the Resistance. Since the New Republic has their heads in the sand re the First Order, Han decides (in lieu of his separation from Leia) to go off and recruit allies from the galaxy’s fringes. That way we get the Solo of old (as per TFA’s intention) but with new noble purpose that doesn’t negate his OT arc.

Similarly a disillusioned Luke with the weight of his own legend bearing down on him after his failure to train Ben Solo could absolutely have been conceived without backtracking Luke’s arc to pre-ROTJ status. As with Han, we could have had new challenges and new circumstances that necessarily resurrected the heroes’ old selves in a progressive rather than regressive way.