CNC routers and laser cutters are now common machines. Not ubiquitous, like a hammer, but they are common enough that I can send a pattern for cutting, or visit a lab and operate one myself. However, they still remain expensive, industrial machines.
Makerslide took the idea of a standard aluminium extrusion frame system, used for building custom frame structures, and added a v-profile to make it usable as an accurate linear bearing system. And created the necessary combining hardware, v-pulley wheels, mounting plates, eccentric adjusters for the pulleys and belt drive attachments to create a linear bearing system that can easily be used for motor control.
Makerslide is intended to be a standardised solution to linear drive systems for the home builder. Aluminium extrusions need a certain amount of capital to produce, and since Makerslide successfully raised five times it's goal, is now manufacturing and shipping rails and the other associated parts.
Then, a month after Makerslide's Kickstarter success, the Project Shapeoko's $300 CNC machine was funded. And a low-cost CNC machine that is now available as a kit. It uses the Makerslide system as it's major structral components to keep costs low, while allowing good accuracy; and this means that it's now possible to own a desktop CNC machine for as low as $338 (as of time of writing).
So with aluminium extrusions extended to create linear bearings; in turn extended to a complete CNC platform; run with open source motor controllers, built upon the open source Arduino board and powered by open source CNC controller software: the cost of a CNC machine is falling steadily into the realm of the hobbyist.