How it affected their expenses? A big corp leaving lessens services utilization which might help if NJ was paying a hefty premium for over-using their infrastructure.
A good theory but doesn't apply here, but I did leave out a key piece of info: the largest drop has actually been in income tax ala large hedge fund managers who have fled the state. Carolina Panthers owner and billionaire David Tepper is one recent-ish high profile example, but there are many others. Corps like Honeywell aren't an infrequent sight either. New Jersey's revenue has fallen YoY since the loss of Tepper et all.
The insane part of me here is NJ politicians keep clamoring to raise taxes more. It's almost as if they heard De Blasio's campaign slogan and thought it was a great idea.