It also highlights an interesting change in engineering and product development that has happoned in my lifetime.

It used to be, when this Armatron was made, electronics and computers were magic and mechanical engineering, real complicated kind of mechanical stuff, was common and the slillset to do it was similarly common. In that world it makes sense to have the whole robot arm powered by one motor that constantly spins, with mechanical clutches and linkages deciding what moves when. That's because electronics and mechatronics like motors and encoders were still expensive and new.

Now its the opposite. In general, if given the choice between a complicated mechanical solution and a "simple" electronic/computer solution we choose that. Simple is in quoted because modern electronics and computers are far from simple. The manufacturing of a modern semiconductor rivals the Manhattan project. But is seems simple because we can just buy it at best buy and program it to do things. You can easily find lots of engineers to do something with code or an arduino, but finding someone who can design a fly ball governer, or even know what that is and why it matters, is rare.

Now days there are tons of cheap robot arms that have a servo motor for each joint, because servos are cheap and complex mechanics are not.