Delamination is not rampant in the RV world. Very few RVs have delamination of the siding when compared to the total number of RVs on the road.
Good preventative maintenance will keep water out. Our current 5th wheel is a 1994 model that we have had since new. It has never been covered and has sat out in the weather 24/7 for 23 years. 2 years ago one small section of the siding showed signs of delamination. It was due to a leak around one window. Because I was taking care of my 90+ year old dad with dementia I had stopped doing routine inspections and maintenance so the 5th wheel and our house suffered a little.
Preventative maintenance is important...
