Note that verse 26 is the real conclusion to this part of the story. The people have had wars, and they have been wicked and idolatrous. Just as the Jaredites had enjoyed the blessing accompanying the land of promise because of their righteousness, two generations of warfare, wickedness, and idolatry jeopardizes that promise. They repent and not only avoid being destroyed but begin to prosper again. As for Shule begetting sons and daughters in his old age, although such a feat is not impossible, it may also be part of the formula indicating prosperity.
Redaction: The moralism of verse 26, combined with the firm reiteration of the land’s promise, suggests that this is Moroni’s conclusion rather than Ether’s. While Ether could certainly have moralized as well as Moroni, Moroni’s editorial hand is so heavy in Ether that it is more likely Moroni who develops and makes explicit the moral lessons.