Literature of Controversy: Is morality a matter of time?

Each era has its share of books deemed obscene and unfit for public consumption. Offences range from moral depravity in the fields of marriage (Madame Bovary, Jude the Obscure), sex (Most things by Oscar Wilde and Henry Miller), mental health (Suddenly Last Summer by Tennessee Williams which also deals with sex), class (Martin Amis, Gustav Flaubert, DH Lawrence), religion etc. These are just a minute sampling of the novels and authors that create massive upheaval and unrest in the hearts of the guardians of social convention.

The reactions to these troublemakers rarely seems to differ: stifle it, supress it, wipe it out of public consciousness. The more important question is not how do we deal with these literary subversives, but moreso does the content change as we progress. Does our sense of morality evolve, or only the extent of our willingness to ignore the underbelly of liminal activities and subject matter? Are there certain inalterable goods and evils in the world determining our acceptance and rejection of literature, or is morality only a matter of time?