What Just Happened?

I found a car that I want. I've done as much homework as a consumer can do without talking to a salesman.

I pull up to the car lot with my gas tank on E because I have no intention on leaving in that car.

Now, I believe the car is overpriced because I can drive 50 miles down the road and buy the same car with half the mileage (15k vs 30k) for nearly the same price, but I figure we'll negotiate something and I'll leave in a new car.

I walk into the building, meet a salesman, we go on a test drive. He isn't very conversational on the drive, but he does admit that he doesn't know much about this particular car.

We get back to the car lot and I'm parking the vehicle when his phone rings. It's another prospect calling with questions about another car he is more familiar with. She has a question about the interior. He tells her that he will FaceTime her in 5 mins (indicating that he was already done with me).

Once we parked, I ask about the price and mention the car up the road for the same price with half the mileage. He says, "Then you should go do business with them" and walks away. I'm assuming to go FaceTime the other prospect.

So... I'm trying to figure out where I went wrong that the guy took time out of his day for a test drive, but didn't even try to sell the car.

Is there no incentive to sell a used car? I'm just trying to figure out why my experience was so different from my expectations.