Quality

All I did was take the DOT numbers from that chart and 2022 article.

[12.2 yrs (2022) - 6.5 yrs (1972)] / 6.5 yrs = 87.7% increase of average age of vehicle on road.
Part of the equation is affordability. When I was 16 years old, in 1979, I had a 1968 Fairlane 500, an 11 year old car, paid $800.00 for it. Today at 59, I have a 1990 Bronco, a 32 year old truck, paid $1500.00 for it 5 years ago, and a 2002 Taurus that my wife drives, a 20 year old car, bought 3 years ago for $2000.00. I also have a mortgage, utility bills, property taxes,retirement investments, and 3 dogs, but my hourly wage is ten times what it was in '79, yet I can't even consider a new or even a few year old vehicle and the debt that comes with it, simply not possible for me at this point.
I did not include my 2 classic cars as they are not daily drivers, and the investment in them is a hobby.