Except generally pre-owned is short for certified pre-owned like it is here, which means you get a much better warranty than buying on the used market.
You're paying for that warranty though. If you really want one, you can buy one yourself from one of several competing aftermarket warranty companies.
Used car dealers suck, in every way. They add zero value other than having a selection of cars in one place, and possibly a selection of lenders for financing if you need that. They also know every trick in the book to get you to pay more for the car than it is really worth.
Best way if you have a little time to do research and watch the local market is to buy a car from a private seller.
I asked a used car salesman once, "what do you do to these cars after you get them" and he said "nothing." They get them from the auction and put them on the lot.
Now maybe some dealers do a little more. I am a bottom-feeder when it comes to cars. But stands to reason that any money they spend on the car is less profit for them when they sell it.