I think that for these big corporations the value of individual "knowledge workers" isn't that great, so they can afford to keep them in rush hour traffic and not have them operating at their peak (see also open office plans). I mean they don't need so many highly skilled and innovative individuals. That's why I don't get the relatively high salaries at eg. facebook. They need maybe a handfull (10-100) of extraordinary people, the rest can be mediocre at best and get the job done. I mean it's a website and selling ads for christs sake :)