The rich never cared about the city. With the money they earned working for corporations, they bought those who lived on universal basic income and used them as tools to satisfy their whims in marble penthouses high above the city.
With their basic needs satisfied by corporate alms in exchange for submission, the weakest individuals spend their days fulfilling their primitive urges in the most perverse ways possible. Social norms are no more.
The 2080s marked the beginning of degeneration. The universal basic income paid out by five corporations in exchange for control over all the continents caused the majority of society to withdraw from real life, spending their days stimulating their neurons via direct interfaces.