Actually dealers are struggling to get/keep used inventory and often pay premium just to have inventory to turn over. I have access to dealer auction data and I am mesmerized what prices some of the cars are sold for (between dealers or returns off lease). Seen places like Caravan selling cars at loss just to show volume of inventory movement and to help keep the stock up.
Dealers want the volume and in current times it is very simple. If you know how to sell and buy and have vehicle which is in a short supply you can do some amazing deals when trading it in for new. When negotiating with dealers - the above post mentioned one of the tricks of negotiating new first and adding trade to the picture later, next big is negotiate with internet department and not directly with sales, next one to be willing to travel up couple hundred miles to pick up your dream car - local market may not provide best deals.
I flip cars way too often (have a problem). Sold four cars in last 15 months (16 LC, 20 4Runner, 20 LC, 21 GX460). Out of the four only 20LC was sold privately and the buyer was willing to pay premium. In other three cases dealers offered more than similar private listing and guides as KBB, Edmunds, etc (btw in most cases listed privately first to see if can get better prices then dealers after tax advantage) In all cases got better from dealers. On the latest two sold to dealer (last 6 months): 20 4Runner owned for 9 months & lost $500 when trading it in for 21 gx460. Then traded it in the GX460 after 4-5 months of ownership for 20 LC HE (made couple hundreds on GX). BTW I have never paid over invoice on any new with 21LC HE being the latest which I got the last week of January
So getting a great price for a trade is not a big challenge, but getting a great deal on new is more of challenge. Some hot cars like the new Corvette, Escalade, 911, Taycan are often selling way over the sticker. LC is a hit and miss looks like it based on late pricing discussions. Definitely I was the lucky one who was able to get it below invoice after prices spiked up after the announcement of LC discontinuation in US.