Nephite Priest and King

Two interesting things about Mosiah 25

First, Alma is I believe the first high priest who is not the king.  Until then the kingship was also the high priestly office.  So the king later stepping down to create the judgeship isn’t just an ideological change, its because for the first time the Nephites don’t need a king to keep their religion going.

Second, on demographics, there’s an interesting verse here:

And it came to pass that king Mosiah granted unto Alma that he might establish churches throughout all the land of Zarahemla; and gave him power to ordain priests and teachers over every church.

20 Now this was done because there were so many people that they could not all be governed by one teacher; neither could they all hear the word of God in one assembly;

The Book of Mormon tells us there were a lot of Nephites, plus there are things like Sherem trying to meet Jacob for the first time.  But then there are these two verses.  Remember, most of the narrative of the Book of Mormon was written by Mormon and Moroni, who were the heirs of a large, complex civilization.  It is unknowable the extent to which they read into the record their own assumptions about how it must have been based on the civilization they were familiar with, but it is possible that they did.