I don't see how that particular issue is baffling to you. These coils might not have been so cheaply and readily available back then. That happens all the time with proprietary parts.
It's baffling that an experienced mechanic wouldn't know that there's often a 2x-5x price difference in "genuine", "OEM" and "third-party" auto-parts. It's something you usually learn the first time you repair your car as an amateur.
So he knows about that, but "I couldn't wait for overnight shipping, or otherwise I could have replaced all the coils for the cost of just one OEM one at the dealership" doesn't build the same amount of YouTube drama.
