We have a Newmar Ventana LE, which is not all electric. When we were at the Newmar factory I asked our tour guide why they were putting so many residential refrigerators and flush no-frame windows on their motorhomes. The answer was: As you know we only build motorhomes to order. When a new item comes out, like residential refrigerators, we offer it as an option. When 75% of the orders request the "option", the next year we make it standard.
My point of this is, with Newmar, at least, the choices we are talking about here are clearly "market driven". I suspect this is the case with other manufacturers also.
Ed Headington