How to maintain a prosperous middle class?

A prosperous middle class is essential for several reasons: To maintain social mobility, enabling working class children to access the middle class. A lack of social mobility leads to strong social and political tensions; To sustain demand for goods and services, and in particular to provide a sizeable market for the new goods and services that result from innovation. A prosperous middle class requires: First, that a large number of middle class jobs remain (industry, industry-related services) relative to high - skilled jobs (new technologies, finance, etc.) and relative to low-skilled jobs (domestic services); Second, that middle-class wages (which can be proxied by the median wage) grow at a normal rate, at the same pace as productivity. It is clear that the middle class in OECD countries is not prosperous today.