TRUE OF COURSE ITS A VERY WELL KNOW FACT
Civil War > Roaring Twenties > Great Depression > Reconstruction
Prohibition would have failed regardless of the atmosphere, because people like to drink alcohol. The permisive attitude of the times (mild compared to today) meant there was little social stigma attached to those who ignored prohibition. People finally came to realize that all they did was stregnthen the mob and lose tax revenues with Prohibition.
The answer is: The middle colonies experienced economic growth as cities such as New York and Philadelphia became centers of trade.
When both new york and Philadelphia become the centers of trade, a lot of investors became interested to inject their capital into these two cities.
This created a lot of job opportunities in both of these cities, making the middle colonies around them to experience massive economic growth and increase in the number of modern infrastructures.