Anyone can read a checklist Mike. What you are forgetting is that a caravan or king air is often flown SP. That means the pilot has to FLY the aeroplane whilst dealing with the emergency, single crew? - try that on your next OPC - unlikely. I doubt you grasp the amount of spare capacity that would be needed in this scenario, no multi crew cockpit here! Most of these guys who fly twins & hi perf singles SP for a living rehearse these scenarios pre firewalling the throttles.
They live longer that way.
Don't underestimate a competent charter pilot!
As for seeing every possible emergency, twice a year in the sim? We all know that is impossible.