That's the big difference between Zim and every (I believe) other country in Africa. The two year apprenticeship is, I believe, unique to Zimbabwe.
If you ask a Zim PH, they will spend that time - or longer - doing just about every job, grunt and otherwise, there is to do in a hunting camp, and doing it multiple times. Even once they get their PH license, the licenses are restricted to plains game until they have been on a certain number of dangerous game hunts. I had a PH I wanted to hunt with in Zim, but he couldn't hunt elephant - had not bothered to get that 'stamp' even though he'd been hunting for a decade. So we got another PH to do the hunt, and it resulted in my original PH becoming eligible for his elephant stamp. Same for all DG.
The result is that while there are great PHs in every country, you can generally rely on the skills and ability of your Zim PH. Personality, well, that's a bit tougher to train for!