Perhaps he should engage listeners and find out why, what, etc.? They're consuming the product. Also, try to get feedback from one-and-done listeners.
Moi? I don't have time or interest in casual chat and then get to the end with nothing taken away. I can't invest time unless I'm confident I'll at least breakeven.
I would find a way to make it easier and funner and reduce the 6 hours.
Otherwise it's a marketing success/failure.