Cars don’t break down as much and last much longer. A 20 year old car nowadays can still be perfectly usable. So in effectively they did get cheaper, just buy used (at least that was the case until 2020..)
Same, also one that is 40 and one that is 60. There hasn’t really been an increase in reliability over time. The difference between manufacturers has always been the defining factor. Simply compare a new Nissan to a new Toyota and you’ll see what I mean. Project out resale value 10 years and you’ll see a dramatic drop in value for the less reliable one. It was cheaper to manufacture, used lower quality parts and engineering and the result is wildly different reliability.