All the same? Not IMO!
First Class A: 1977 Pace arrow 27 ft., Dodge 440 chassis. HORRIBLE floor plan! If anybody was in bed, the bathroom was blocked.
Second coach: 1988 Suncrest 32 ft., rear bedroom. Nice coach, well laid out, hated the GM 454 chassis.
Class C: 1995 Tioga, Ford E350 chassis, 460 engine. Adequate.
Current Class A: 2002, Ford V-10 chassis, one slide (see sig). VERY happy, nice floor plan, tows the Jeep or the PT cruiser with no trouble.
All the same, just a box on wheels? No, I don't think so. there were vast differences in all of them.
I understand the point being made by the OP, I simply don't agree with it.