How do certain topics and themes stay relevant across time periods, while others do not?

Themes that are relevant to many people across generations generally remain relevant over time. Readers across different time periods can relate to such themes, such as socially significant themes like politics, gender dynamics, class inequality, industrialization, types of relationships,

For instance, literatary works that deals with gender dynamics or class inequalities are as important nowadays as it was centuries ago since the remain being a matter of concern for society.