Question

In the late 1970s, manufacturers of designer blue jeans opened up a new market by appealing to consumers on the basis of ____________.

Answer 1

I believe the answer is: Durability.
The main target market of Jeans product in the late 1970s were workers in mining sites.
The pants that made with jeans are cheaper and made with stronger materials, which make the products favored by the people who are working with hard physical labors.