Because you are acting like the market of "new car sales" is a completely free, rational market. Which it isn't.
As an example, look at Mistu Evo 10's. They manufactured a ton, but MSRP was $45K+ for what is a shitacular car overall. Most were advertised at $50k+ at dealers, zero room to budge. I've seen evo's sit on lots for YEARS. So, this isn't really a case of price discovery. Its a case of a monopoly (the dealership) artificially limiting the supply of a product.
And then what happens is the manufacturer goes "huh, we aren't selling any of this performance car, the market doesn't want it" while the real issue is the ridiculous gouging.
End of the day, just because someone manages a multi-million dollar car dealership does not mean they actually have a clue, or are operating in the most rational method for making said dealership profitable. Hence the outrage.
Another example, 3 or so years ago I was SERIOUSLY considering buying a Sonic RS as a daily driver. One dealer in Edmonton had a two year old model that hadn't sold, exactly everything I wanted. Pricing was very good, but they wouldn't finance at a good rate (5.49% LAWL). I tried to explain to them that if I bought the car at that rate, I might as well get a brand new model that would be inherently worth more with 0% financing, as the paid price would be the same, and the car would have more value over its lifespan and even just as it leaves the lot. I was seriously ready to buy. Nope, no interest.
Nobody wanted this f*&king things, they had a way to get rid of it, and they didn't take it.