[CyberDildonics]

People build their own furniture all the time when they buy things they need to assemble from ikea, target, etc.

People wire up electrical components when they hook up their TVs, computers, surround sound, etc.

People do their own plumbing when they hook up garden hoses or put on a new p-trap.

Mounting a TV bracket into studs or even hanging a picture is some slight carpentry.

These things work because there are standard connections and good design, but in many cases it took a long time to get to the current designs that are simple enough to be intuitive and come with any tools needed.

Standards and design have made these things possible. Even building a computer is similar. Many people's automation needs aren't so complex that they need to venture out of reasonable constraints.