I have to disagree with you there. New Bedford was a shipping port, albeit smaller than Baltimore, but still reliant on fishing and trade just as Baltimore was.
As to Pittsburgh, being a native and having some parts of the family going back to the Civil War era, the average working man there, as well as his family did far better than their counterparts in the southern states.
The only relative I know of who was a veteran of that war was a great uncle of my mother who was born in 1914. She knew this elderly uncle when she was a young child.
Looking at his records, he was a worker in an iron foundry when the civil war broke out. He listed his occupation on his enlistment forms as a 'puddler.' They were the guys who walked right up to the furnace, took a sample of the iron and poured it into a mold and decided if the entire heat were ready for a pour.
That was a tough and dangerous job, but he owned his own home and had a family when he enlisted in the Union Army.
Comparing his circumstances to that of a slave is night and day.
Our own area (east of Pittsburgh) is full of people of Eastern European and Italian descent who will tell you just how horrible their ancestors had it in the local mills before the advent of unions.
It is why so many of them still instinctively pull the "Democrat" lever even if they have almost nothing in common with the modern version of slavemasters.