Robots in factories can only do one job, building the same car over and over again.

Which is neither here nor there.

It's still automation (which, as a concept, doesn't require being able to do multiple jobs, or even to do a single job from start to completion).

A mechanical system that frees a human from having to do do part of a job is already automation, and can still save tons of time and worker costs/effort. E.g. a system that automatically assembles 95% of a car door, and a human just has to come in at the end and attach some hard to automate part, is still better than the human having to assemble to whole door.

Have you ever worked in construction?

Again, a non sequitur. Is there a point here?

The point is that it's easy to, from a distance, think that something is just like another thing. Without experience in a particular domain, you really don't know how things work. No two walls are alike.