The process of producing lumber is largely automated.

The process of producing concrete is largely automated.

The process of producing drywall, mud, paint, nails, tools, wires, switches, pipes, are all largely automated.

The process to create the architectural designs and blueprints for the house are largely automated.

The process to create the electricity, fuels and vehicles needed are all largely automated.

To make a house, people used to draw plans by hand (if at all), chop the trees down with an axe and/or saw that was made by hand by a blacksmith, shape the timber with hand tools made by the blacksmith, fasten things together with hand-crafted joinery or nails hand-made by the blacksmith. All the materials were transported by hand or by horse and lifted onto the structure by hand or manually operated hoist. Every part of it, including the production of all the tools, was previously done by hand.

The invention of the assembly line opened up the possibility to eventually automate virtually everything except the final assembly, and we have robots that can be made capable of doing that autonomously as well. You can buy pre-fab homes where all the major sections are built in a factory by robots and shipped out to the construction site and attached together.

Construction is far more automated than what you make it out to be.

I mean i could have just as easily described the process. Cutting a trench is a process, most of which was automated by the back hoe, conveyor, dump truck, and laser levels. Before, 20 or 30 people would be required for trench work which is now often done by a crew of two.