I am Sarah, 40 years later - and now, I am able to buy new cars - because I had my priorities straight when I was young.
That's my take also. Sarah can afford a new or newer car 6 years later, with no interest payments but Sam either keeps driving what he has, or buys a beaterif this one gets totalled, or stays in the vicious circle of endless payments.
Btw, still 30% of new value after 10 years? Can't do that here, but new car loans are cheaper and I guess that inflated cost in the US keeps used car prices high aswell. 10-15% of new is my reality after 10 years.