Amazing Raspberry Pi Driven 3D Printer reduces Mechanical Engineering

I don't know much about Raspberry Pi, but this is this is a 3D printer set up that is being run with Raspberry Pi. It has greatly reduced the amount of mechanical engineering needed. Seems like this printer would only cost a $100 or so to make (correct me if I'm wrong), and it may be able to do things a regular 3D printer wouldn't dream of. Is this really a feasible option for a 3D printer? Do you think we could begin to start seeing more affordable printers being made using Raspberry Pi?

https://www.youtube.com/watch?v=sc1TodqOurQ

This is pretty cool. Is there a printer being designed using this type of technology? This printer looks very simple hardware wise.