The average new car price in the US is over 33k, I could not find adjusted numbers for 2017 for a source. New-Car Transaction Prices Up 2 Percent In March 2016, Along With Increases In Incentive Spend, According To Kelley Blue Book Most Americans cannot afford a new or even a lightly used car with the median average income in the US.
Also considering the fact that Americans have smaller amounts in their savings you will have to have longer loan terms to sell cars. 5K down a 40K car is stll close to $700 a month on a 5 year loan depending on taxes and fees.
It amazes me that people still buy cars with the escalating costs of a new car. Once you add in insurance and gas you could be in a new car for $800 a month. 72 - 84 month car loans will become the norm with the average ownership period for a car being 11 years. Homes and cars keep going up but wages do not. Tough times ahead.
40k for a damn car

It's because people are willing to get into these stupid loans. Car prices will continue to rise as long as people keep doing these loans. Again like student loans, take away these dumb options and you'll see the price of cars/college drop dramatically.