Joshua

Or they could've y'know.....

Done two arcs in the same series at the same time...? Like Dragonball, and various other animes have done in the past?

Have Sasuke and Naruto deal with the world ending threats, while the next generation handles more local threats to build them up to a point where they can stand beside Naruto and Sasuke fighting the big threats?

Thus Showing the mentor generation as a goal to aspire to, potentially even surpass, while also humbling the older generation by showing the errors in their methods and ideals? Show growth for both?