Yeah it really is sad. Unfortunately these types of sales job aren't really highly sought after and believe it or not most dealerships would probably run off a knowledgeable candidate that was looking to work there on the side. Many of the full time reps know very little about the units, mostly because they don't use them. Hard to RV when you're stuck working 6 or 7 days a week shagging RV's.
Sales in general sucks the big one. Naturally when the job kind of sucks it can be hard to attract good talent. Thus you end up with idiots just looking to make a buck before the move onto the next thing. Mindset like that doesn't make you super interested in really taking the time to learn and you'll say whatever you have to for a sale.