Mormon sees all of these things, but rather than ascribe them to the acceptance of the social norms of cultures surrounding the Nephites, Mormon ascribes these traits to the influence of Satan. There may not be more than a technical difference. The world is what Satan uses to tempt us. In many ways, the temptation to accept the world is even greater today because it is so easy to gain the trappings of the world. We may or may not be able to afford the more expensive home, but credit allows us to live in it as though we could afford it. We might not need a certain type of car, but we use those vehicles to express our self-impression of where we want to be seen in society. There are so many more ways that the world may entice us, that today we may be even more susceptible to this Nephite problem of accepting Satan’s substitutes.
Narrative: Mormon has set the beginning scene as one of righteousness. This was induced by great desperation in the face of need, but it became righteousness that the Lord would honor with victory. Mormon painted the people as truly united after that incident. Now he contrasts the earlier righteousness with the rapid decline into accepting the world once again, and accepting the temptations of Satan. They have, in the space of two short years, come to “a state of awful wickedness.” It is this awful wickedness that will cause even further destruction among them.
Typologically, Mormon is teaching a lesson from history. Righteousness leads to prosperity and peace. Unrighteousness leads to destruction. At this particular point in time, Mormon is emphasizing the destruction, which is first social, and will then be physical as the Atoning Messiah will come, and be heralded by a tremendous physical destruction of the wicked.
For Mormon, even this descriptive history will be typological. This wickedness followed by tremendous destruction is a type of the final destruction of the wicked with the Messiah will come again at the end of the world. When the Atoning Messiah comes (and he comes soon in this narrative) he will physically destroy the wicked. When the Triumphant Messiah comes, he will also physically destroy the wicked at that last day.