Ye you need to know what you are doing of course.

My point is that houses are not like electronics were ICs have become like unsolderable for DIY due too small size SMDs.

I could do what a carpenter does, if I just were competent. Which I am not.

I feel the same. Yet I know a couple, music teacher and beauty therapist, who built 2 houses themselves.

How did they handle wiring and HVAC? The foundation and drain tile?

All of that is pretty simple if you try. Especially the Wiring. You just need someone licensed to come hook up your breaker box.

My understanding is that you can pull the wires your self but should not connect them without a pro for insurance reasons.

And the foundation you need excavators and trucks with filler material and maybe concrete so you need external help with that.