some day every city will have one
From one of the essays in Lewis Thomas's very nice book "The lives of a cell":
Even when technology succeeds in manufacturing a machine as big as Texas to do everything we recognize as human, it will still be, at best, a single individual. This amounts to nothing, practically speaking. To match what we can do, there would have to be 3 billion of them with more coming down the assembly line, and I doubt that anyone will put up the money, much less make room. And even so, they would all have to be wired together, intricately and delicately, as we are, communicating with each other, talking incessantly, listening. If they weren't at each other this way, all their waking hours, they wouldn't be anything like human, after all. I think we're safe, for a long time ahead.
Oooops.