In "Everyday Use," the differences of perception might have something to do with generation, but not everything. The story is set in a relatively modern period (late 20th century, considering the Johnny Carson reference). And since this would follow the Civil Rights movements of the 1960s, there had been more general awareness of history and cultural heritage, particularly with African-Americans. And Dee would have been exposed to this kind of education at college (Augusta). Although, Mrs. Johnson notes that Dee was always dissatisfied with her life at home, so she was inclined to embracing other cultural lifestyles. However, since Dee really got into her African heritage at college, her changing perceptions had to do with her personality, being a generation apart from her mother, and because of the different culture at college. So, it has something to do with generational differences but also to do with geography and different cultural education.
Another example that shows that it is not merely a matter of generational differences is that Maggie does not share Dee's outlook. Maggie has had a harder life than Dee and this could be why she chooses to stay close to home and not risk some new lifestyle. But on the other hand, Maggie is much more genuine than Dee. Maggie embraces her mother's heritage while Dee is condescending to her mother and only interested in more remote cultural ancestry. When Dee leaves, she tries to tell Maggie to change:
"You ought to try to make something of yourself, too, Maggie. It's really a new day for us. But from the way you and Mama still live you'd never know it."
Maggie is satisfied with living the way she and her mother live. When Dee leaves, Maggie smiles: "But a real smile, not scared." Maggie and her mother have similar perspectives about family heritage and culture. So, generational differences do not play a role with Maggie and her mother. With Dee, the generational gap plays a larger role.