Do you enjoy watching How It's Made? You're in for a treat, then. Valve has published a video of the automated production line that builds Steam Controllers, complete with Aperture Science robots and a few miles' worth of conveyor belts. Watch it here:
Quite mesmerizing, if I may say so. There are a few humans in the factory, but they're probably just some of GLaDOS' test subjects. Valve says it "kind of went overboard" when building this facility. In the company's own words:
To achieve our goal of a flexible controller, we felt it was important to have a similar amount of flexibility in our manufacturing process, and that meant looking into automated assembly lines. It turns out that most consumer hardware of this kind still has humans involved in stages throughout manufacturing, but we kind of went overboard, and built one of the largest fully automated assembly lines in the US.
Valve then goes on to say that robots are awesome, and that is totally correct. This was a triumph. I'm making a note here: huge success.