Most hives have some moth presence. The difference is that strong hives tend to control the larvae. They stink and kill them. A weak hive is lethargic and will not attack the larvae, thus it's sadly easy for wax moths to take over a weak hive. I speak from exprerience.
Couple of summers ago, I extracted and left one already kinda week hive too low on honey. Came back to a month later and the hive had been overtaken by moths. It was a nasty scene.