Yeah, society moves on. Values it once assigned to certain material things fall out of use in favour of others.
It's as if he views the value we socially place on an object (say the price of a car) as a fundamental property of that object.
Like; his position seems to be that if human beings were suddenly made extinct, an alien species that discovered that car would give it the same value.
The object only has value because we say it does. Not due to some kind of inherent quality of the object that exists independent of our social agreement as to that value.