I guess that dealer doesn't care about sales. Find another one.
Some dealers will not take trade ins no matter what. A very highly respected guy local to me recently unloaded $225K of gear to a wholesaler after he got sick of it. He is very knowledgeable by not patient enough to deal with the used equipment complexities. He used to do it, but doesn't need to now.
Another guy is sitting on tons of stuff and will only take trades he knows he can sell and with him it is only on consignment. And he forgot to pay me once when he sold something of mine. Oops....never bought anything else from him.