Except that there is now high-end office space and swanky malls sitting on the land where the mills used to be.
Those lands had nothing but rusting hulks on them. There is plenty of land to re-shape mills these days and most likely better designs to boot using said new land.
BTW, I had to laugh my ass off today downtown when the PGH Verizon union scum hired a bunch of EBT and welfare types to walk along shouting "get up, get down, Pittsburgh is a Union town" and not even realizing what drove the city into damn near the dustbin of history in the first place. Unions. I could care less about downtown blacks or the unions; perfect company in squalor and incompetence.
On a side note, it is very comforting to hear some leftists I know now calling Unions what they are, parasites. They are now getting that unions are sucking the very companies dry that they work for. What's that about a mugged liberal?