I have been thinking about how I view the difference between a machine (complex or not) and a 'robot' and I guess it gets down to the ability to learn or improve.
A machine repeats the same steps, time after time, never varying beyond hard-coded limits. In my view, a robot learns or adapts to its environment. A robot's behavior may not be entirely deterministic. There probably isn't a hard-coded state machine at its core.
There has to be a difference, in my view, between a machine and a robot. Most of the stuff called robots are really just machines. There may be a lot of sensors, certain behaviors pre-programmed, whatever. It's still just a machine. My drill press is a machine. So is my CNC mill. Clearly there are orders of magnitude differences in complexity and capability but they're still just machines.
I don't know that I have ever seen a robot, using my definition.