They were probably 100% cotton back then. Even if they were pre shrunk they would still shrink some more.
Shrinking doesn’t all happen the first time they are dried.
The neighbor girls used to wet the jeans and wear them until they dried to get that perfect fit.;p
<- ties an onion to his belt, which was the style at the time.
What the hell kind of jeans did you wear?
They were in fact reversable pyjamas.
Damn, they still make them!
http://dickiesonsale.com/jeans3.htm
When a man outgrows his youthful vanitiy and assumes the mantle of adulthood, the Dickie aisle beckons.