Its still wrong to suggest that older cars are used less.
That is true they will buy a new one every few years.
That bit makes way to many assumptions. The main one being that you assume that a car with high miles has been worked harder than a car with less miles. With cars mileage is irrelevant, hows its been driven its what important. I have put 6000 miles on my car in 9 months which is not a lot, but i have ragged that car about and driven it into the ground. Mind you it only cost me 310 quid. If a car has done 200000 miles but been driven well it will be in better condition than one with 30,000 that has been driven by me.