That's a very valid point you make there.
There are even Tradespeople over here, that don't realise why it is that things are done, the way they are.
I'd like to say that having a good grounding in Fault-finding techniques and using logical thinking to effect a quick solution to a problem, would do no apprentice any harm.
And one thing that wouldn't go amiss is teaching how to identify different types of services within a house/building:
Wildly off-topic, but just trying to give an example, there have been instances over here, where apprentice Plumbers have attempted to cut through live metallic conduits (usually the Service Main) in the roof void, thinking that they were water pipes.
And there have been times when Socket-Outlet circuits have been connected to the Night-Rate side of the installation.
Let's face it, these days if you're not young, you're old - Red Green