Even though there were more highly trained troops with Moroni, it is likely that they also returned to their “houses and their lands” just as did the militia from the land of Manti. Note that this also parallels what we learned in Alma 3:1:
“And it came to pass that the Nephites who were not slain by the weapons of war, after having buried those who had been slain—now the number of the slain were not numbered, because of the greatness of their number—after they had finished burying their dead they all returned to their lands, and to their houses, and their wives, and their children.”
The Nephite army, as with all other Mesoamerican armies, was not a standing army, but one called up when needed.