There are two major players and a few minor players in the RV field. Model and cost differentials are determined by features, so Brand A down the assembly line may have a two burner stove, while Brand B has a three burner stove and Brand C has a stove with an oven.
This is no different that the appliance industry that assembles products with different add-on under various trade names on the same assembly line. Or, the old Ford, Mercury trade labels.
Each company has a marketing niche to fill and adapts the assembly line to those items that are unique to their product. Even the smaller TT players with their own facilities still buy from the same raw products vender pool. It is not unusual to see the same drawer pulls and flooring in a different brand TT that is five years older or two years newer than your own TT.