But what impedances are you looking for? Technically you have two circuits in parallel.
The fact is the worker should be in an equipotential zone where we limit the voltage exposure. The pole where the worker is at should also be bonded. If not, as shown, we have a current divider with the rod rather than with the protective ground cable.
First, we make assumptions about worker impedance and clearing times which lead to the result that a 75 volt or less exposure is the goal (for line work). See substation grounding design guide.
Next, we have to know fault current levels and safety ground cable impedance to properly size the cable, place the cable (that is important for impedance modeling: closer to worker is better), and even control fault current level to keep the exposure voltage below 75 volts.
Then the question is where do we ground? A substation grid is the best, a multi-grounded neutral is next, etc. but the last resort is the driven ground similar to in the video (also driven if we are unsure of the pole/tower ground integrity).
With a great ground like a MGN and proper bonding then the worker is in an equipotential zone and only exposed to the cable voltage drop as discussed. With a driven rod the worker is also in an equipotential zone but the ground needs to have a low enough impedance to trip the protection in an adequate time (and the metal pole/equipement should also be bonded).