Urban Sprawl in Comics Redux?

The latest version of Legion of Super-Heroes mentioned something interesting in passing in a recent issue written by Mark Waid: their version of 31st Century Metropolis runs across nearly the entire North American Atlantic seaboard.

Question: how chilling(or not) do you find the implications of a single city running all the way from Cape Breton to Key West?

Yours, whilst still wishing I'd gotten that Daily Planet Guide to the Legion Worlds project with West End Games past the outline stage,

Dwight