I suppose in fairness, the courses are designed as a starting point. In the same way as a driving test is designed to check the fundamental abilities of a driver. It's not going to deliver a seasoned driver..
I'm sure there must be benefits for someone taking on an apprentice if they have done a course and at least have their head around the theory, even if their experience of real life work is zero.
To stick with the driving test analogy, when I passed my test I assumed I was a confirmed driving god and was subsequently invincible. Looking back and recalling a few 'incidents', I can see now that wasn't the case