Authors create this effect by story-within-a-story. It's not about creating something new and real, it's about embracing the idea of writing stories about stories. 

"historiographic metafiction" is when a text brings in history but put their own spin on things. 

→ art and literature are created by reworking existing texts and ideas

 Ernest Mandel helped popularize the idea that capitalism comes in three stages. The most relevant is late capitalism. Madel defines late capitalism as a time of "generalized universal industrialization. And began around 1945—the same year that World War II ended and postmodernism is often said to have gotten started. Late capitalism is also known as advanced capitalism a stage in which industrialization and commodity culture have invaded more and more areas of everyday life.    

There was a period called enlightenment. In this period, everyone was about order, rationality, science, reason and unity. The movement had a lot of challenges. And as time went on, new movements came in and played a role in society. After romanticism and gothicism, then modernism took over, after world war 1. They were all about uncertainty, alienation and fragmentation. The modernist was different from the postmodernist by expressing a sense of sadness and say the fragmentation as something to be moured. Opposite, postmodernism embraced the idea of fragmentation and used it to reflect and explore the chaos of the world. 

Irony was not just used in postmodernism. Verbal irony is a kind of sarcasm just fancier. Not all people mean that irony is fun. Irony can be fun and bring some smiles into peoples faces. But it can also be used to highlight the absurdity or severity of serious situations. 

In the late modern society, irony had become so popular so it seemed to have lost its impact. Irony can always be an effective literary device. Irony is used in common speech but also in literature.