I would say that's a fair assumption.
If there's heavy discounts on "left over" models, people tend to look there first before looking at "used". All this makes it harder for dealers to move used models, which means they are less inclined to give you top dollar for them. Not that "trade ins" ever get top dollar from a dealer....and if you do, that usually means they are making decent profit off your new car purchase where it covers the loss in trade in. When I'm looking at new cars, I negotiate price and then tell them about the trade in. If the trade in doesn't get what I want, I walk. Pisses some dealers offwhen you negotiate that way, some understand that's just the way the game is played. Most like knowing up front that you're doing a trade in so they can "spin the numbers" to their advantage. I don't play that game. The value of my trade has little to nothing to do with the purchase price or their bottom line. Again, if they don't like that, I walk. It's personal, it's just business.
Plus, around here, most dealers will send vehicles 4-5 years old to auctions rather than sell them themselves. They don't want vehicles sitting around as tied up inventory/cash and used cars that don't look new tend to hang around a lot.
If it's their intention to auction house it, you usually get even less on trade. At 3 years old though, you might be ok on that one.
Yes, I've worked at a dealer in the past. But it was a fairly long time ago and one thing car dealers are good at, is finding ways to profit off thier customers.That is their job after all.....