Why can dealers still get away with such terrible advertising practices?

Our local VW dealer had an incredible promotion a couple of months ago - at least it was incredible on the face of it. They had a media blitz advertising $8000 below MSRP on all new cars. Remember the old adage about 'if it seems to good to be true' ? Well naturally they weren't selling new cars that cheaply - no dealer could - they'd lose their shirt if they did. What was curious in this case was that there wasn't any fine print either. It was only if you went to the dealer and talked to them that you found out what the scam was, and it was this: the cars were all used or pre-owned cars, and yes they were all $8000 below the MSRP of a new car. But how could they advertise this discount on "all new cars"? Simple. The used cars were new to their stock list at that dealer.
The other huge scam is when you see TV commercials showing a really good deal. Buy a Camry today for $uper Cheap! Those ones all do have fine print but it goes by so quickly that you never really see it. In fact they are actually selling a Camry (singular) at that price. It's one particular model, with a very specific stock number in their inventory. Or it was. Of course by the time you go down to try to buy any Camry at that price, the one specific one used in the TV commercial is long gone and you're saddled with the regular price on all the others.
How about the "cash back" deals. Or the ones where they offer to pay you $1000 more than the car is worth? More scams, obviously. Yes they'll give you cash in your pocket, and/or $1000 above average for your trade-in, and they do it by simply adding that on to the loan for the new car. So instead of loaning (for example) $15,000, you're actually loaning $20,000 - $15k for the car, $1k "extra" for your trade-in, and a $4k cash loan. The dealer makes more money, the dealer's finance company makes more in interest and payments off you, and you end up with the same car but more debt than you'd intended.
The crazy thing is that all these practices are completely legal. They simply rely on people's fear of car dealers and unwillingness to challenge the status quo. It's a terrible state of affairs that needs some serious attention.