how can entrepreneur skills can move up the economy of a city from the underground to the mainstream?

Answer 1

basically a good entreprenuer, will try to bring the underground business into the legal light and try to take advantage of the needs of people that are supressed.
thereby bringing in white money into play instead of black cash

for example if its an underground prostitution racket, you can turn it into a high class escrot service and have people pay more , use credit cards etc.