As a side note, I do like how they decided to show Raccoon City as a dying town. And, yeah, it does try to get a John Carpenter-ish vibe: even the font for the title cards is straight out of "Escape from New York". The RPD part kind of feels like an attempt at doing "Assault on Precinct 13" with zombies - except it doesn't quite work. It's a very mixed bag at the very least. I don't hate it but I don't love it either.
I thought that was the dumbest thing of the movie. It's like saying Springfield, Missouri is going to rot and die immediately if their biggest economy booster leaves. Not only is that historically unrealistic (It took many decades for Detroit to get to its current state) but it came off as waaay too dystopian (but not in a good way!) and absolutely killed the atmosphere of the movie. Most disaster movies from the 90's at least had a colorful cast of characters and a vibrant backdrop to keep it rich but this just came off as dead and empty and lifeless.