I think people picture the modern version of scientists in white coats doing all work at the OEM facility. And some small shops, just one guy, have that advantage. He has to do it all. But in a shop with multiple employees, hire a qualified circuit technician and put him to work terminating cables and he will quit the first day.
Some small shops in small towns have low turnover and eveybody bowls together on tuesday night and they get very qualified people that say in their jobs for a long time, lots of pride.
But in urban areas, turnover is cruel and the "new guy" has to be trained often. Thus this kind of work is often outsourced to countries where experienced adults make $25 a day or less.
as my dad said, if you want something done right, you have to do it yourself. Not totally true but for sure a good answer if you've spent your life doing things.
Jerry