Well, you’re operating on a fact set that sees Manhattan rental rates as being similar to Jersey City rates since they’re all part of one big regional market. I see them as being very different markets within the region, now serving very different economic classes in a way that they didn’t before the mid-1990s.
There was a time when Manhattan strove to be as economically diverse as Hoboken, so the people who made the city run could afford to live there. At that time yes, they might have been considered one large market with some slight internal variations. That time is decades past.