The sticking point is what licensed tradesperson would sign off on work done by another unlicensed person?

Here, I've often done full 240 V AC wiring and gas fitting for houses, workshops, abd glass blowing | ceramic studios .. but never connected or made any of it live, instead I've called in local tradespeople to inspect and test the work from end to end, just as they would check the work of an apprentice, and then certify it.

It's been cheaper for me that way as well as allowing for better control of how I want things to go, it's been less hours work for them in an area where they're in high demand and a bit of a win-win.

On at least two such jobs I've been advised to change some details as the most recent codes had changed and required things I'd been unaware of, no drama.

And no, in general university electrical engineers don't leave university with the practical trades skills to wire looms between power plants and racks of mills, screens, and grinders drawing high voltage high amp three phase and requiring complex control and instrumentation circuits.

They can sketch that out but they rarely get the practical cable pulling, wire cutting, box layout, etc experience outside of an actual trade apprenticeship type role.

if you want to cut a hole in your wall to put in a window, it could be as easy as cutting a hole and putting in a window. Or, it could be that it's a "load bearing" wall, and you need to put a wide I-beam over the new window to safely redistribute/bear the load that the formerly intact wall was carrying. Or, you could have chosen a spot on the wall that has a column/pillar that's holding the roof up. Probably you'd choose a different spot, but if wanted that spot you could hire some engineers to figure out a new set of "cantilevers" or "flying buttresses" or (i'm not this type of engineer, I'm just throwing around words).

As the work you do becomes more and more dangerous to more and more people, you need somebody with higher levels of certification/licensure to approve the plan.

an electrician, who has a license, is not an engineer, but a good electrician could become one if she wanted, it would require study and exam passing. Some electrical work an electrician is allowed to do, they can "self certify", but the city might spot inspect it. The next level of complexity they perform the work, but a building inspector needs to inspect. The next level of complexity, the plans need to be certified and approved in advance.

I'm sort of making this up, piecing it together how steam fitting is done (that's mechanical engineering), how air handling is done (also mechanical engineering), plumbing, etc. But this is the general scheme.

some of this is legacy disputes left over from the 19th century. When they were inventing electrical circuits, everybody was an engineer and everybody could do everything, and people just invented stuff on the spot and tried it. After enough people died, it was decided we needed standards. And slowly a white collar/blue collar sort of distinction started to emerge, for work that required calculus vs work that requires knowledge of lots of specific requirements.

Calculus people design cars and planes with smooth sleek shapes, but those items can't be constructed without the other type of engineer saying "hey, that's not strong enough"