Because it's not as fun as a kid using building blocks. You'd just be doing a single job over and over again into monotony and it's filled with permits, inspections, waiting, etc so projects get dragged out and you don't get thr same gratification as you would if it were done faster and all parts done by you.
I know you said that, I just disagree. I think it's in the person. You can reframe anything: air conditioning (horrible), sitting at a desk (oh no), your work not having any tangible results (get me out of here), being indoors all day (why is this happening to me).
