Travel Trailer Construction - Exterior Identification

Can they? With 3 or 4 mega manufacturers left dominating the industry, I submit not many choices for the consumer. Plywood floors are a good example. We all know what happens to them when not if a leak occurs. Then add trapped moisture from belly insulation. Soft floors are the result and very difficult to repair. Airstream on down uses plywood floors. Can you order as an option marine grade? No.