My annual trip to Toledo OH coincides with the great spring migration of RV trailers from Elkhart IN to RV dealers in the Northeast USA.
I pass literally hundreds of RV transporters on I80 and I90 going East as I head West. They are obvious because they have little magnetic signs on the doors declaring their professional hauling status.
Virtually none are using WD hitches. Only the larger >10,000lb models seem to be towed with WD hitches.
Generally they are towed by dually pickups. The trailers are towed with a nose-down stance, much more than you would normally tow at.