Seriously, that's your response to my post? I mean, its not like that's my point or anything...you know how, I said that unless there's big monetary reasons to develop an area. Silicon Valley and cities just might have that, don't you think? Yet you think somehow there's going to be hundreds of millions in sustained development for areas that have dozens of people to try and bring in hipster professionals? Maybe decades in the future we'll see dispersion, as wireless technology and transportation advancements (among other things, access to decent medical facilities is pretty important too, and uh, those are languishing quite a bit in rural areas these days as well) makes it so people can live more isolate but retain the benefits of modern world without much fuss.
Also, uh, did you read your own article?
Plus, superfund sites are not created equal. The amount left by a manufacturing plant tends to be a little bit less than clearing mountains and having giant pits, or mines that snake through an area. Or at least is concentrated in a smaller area. Plus, people in Silicon Valley aren't really "living in a superfund site", they might work near fairly small ones (that were often cleaned up, well about as good as they could be, or are part of an ongoing processing of), but even then most of them are pretty insulated. Not that it makes it ok (and absolutely there's serious issues with toxicity in the environment in and around cities too), but its not even close to the same level.