Why is it that we don't go back to the original mechanical g-code and

Why is it that we don’t go back to the original mechanical g-code and print more parts on a 3d printer? Can we do away with the arduino?

If you do away with the arduino, what connects the servos to the computer? I don’t know what you mean by the first question, it seems that you can pint multiple parts on a 3d printer now.

What is “original mechanical g-code” and how is it different than “modern” g-code ?

If you want to do away with the arduino, you can use LinuxCNC on a dedicated PC. Several people have done this, and I hope to in the near future. There’s been some discussion in the Opensource CNC community here on g+.