Thought Provoking Question

Herrick defines rhetoric as the systematic study and intentional practice of effective symbolic expression.  This symbolic expression ranges from writing and speaking to the arts and other typical self-expression outlets.  Herrick then also goes on to define five main characteristics of rhetorical discourse, an important one being that rhetoric is responsive to a certain situation or statement.  Under the guise of art, how is that famous artwork from the 16th and 17th century are still relevant today if they were created in direct correlation to their time?  Is there a general theme that crosses human nature throughout the ages that allows certain symbolic expression to resonate for many generations and years to come?  And if so, what are some rhetoric discourses today that will turn into a “masterpiece” in the future?