Car sales are likely to go down, but not stay down, IMO. First, the cars (incl. trucks) which were built in the 80's-90's and even 2000's to a lesser extent, are simply not that well built. When was the last time you saw a 5 year old car with surface rust, or even a 10 year old car? Remember the GM X bodied cars and horrid Chrysler K cars of the 1980's? Unsurprisingly, there are a lot of older cars (10-12 years old) on the road than there used to be.
On the other hand, the Wall St. Journal reported that young people are now beginning to look again at moving to the suburbs due to the high cost of City living. That will eventually drive up the need for cars (say 10-20 years). It won't take them long to realize that renting, or leasing, is a more expensive option than buying.
But, you will see a turn away by the younger generation from high end luxury cars as a waste of money. They view cars as a way to get around; not something to wrap their ego's into. So, the manufacturers now have their premium brands selling to average income buyers. I still remember seeing some cleaning ladies loading their vaccum cleaners into a 3 Series BMW. Compared to income, they have really come down.