Sales of RVS over the weight requirement for a CDL would tank. Most people would buy as big as they could fit under the weight cutoff, just to avoid the hassle.
With sales of big, profitable RVS decimated, manufacturers would either go out of business, cheapen build quality even more to save money or weight, or increase prices on smaller units, just to stay afloat. The selection of large units would decline, as there would be fewer buyers for them.
It will probably happen someday. But I don't think a lot of us will like the consequences for our hobby.