I’m afraid you missed the entire point Nick.

I’m not saying to buy a new car and replace it after 5 years, when it is only 5 years old and has no problems inherited from someone else. That would indeed be more expensive than buying used and driving for 5 years.

What I am saying is that instead of buying a car used (say 5 years old) and driving it until it is 10 years old (i.e., buying used every 5 years), you’d do better buying new and driving until the car is 10 years old (i.e., buying new once every 10 years).

And if you were to say that cars these days are reliable enough to drive until they’re 15 years old, then buying new and driving for 15 years will most likely be a better choice than buying 5-year-old cars and replacing 10 years later when the car is 15 years old.