[tsotha]

>I figure in a few centuries, a lot of communities will be massive buildings without any sun exposure anyway.

I would be surprised if that turns out to be the case. People need sunlight to be healthy, and while you could certainly create artificial sunlight it would still cost resources, and there's a big benefit to having most people awake during roughly the same hours.

[jzwinck]

There are massive downsides to having everyone on the same schedule, too. Most infrastructure has to be a lot bigger to accommodate the peak loads. Roads are plagued by "rush hour," call centers have "longer than expected hold times," and coffee shops have to decide whether to ask staff to work short shifts or pay them for periods when they are not needed very much. These things reduce productivity and even kill people.