If I recall correctly, the impetus for Christiansen to even look into this was to answer the question: “why are there so many milkshakes sold in the morning via drive thru?”

That’s a different question than, “how do we make our breakfast menu more popular?”

Now, perhaps the latter question begat the former, but either way it is not a product innovation story, it’s a customer/market research story articulating the shape of customer demand (which I fully support).

If there was a second part of the story - like, McD started marketing milkshakes in their breakfast menu and sales shot up ##% or they developed a breakfast flavor milkshake and sales shot up - then we’d have the product innovation story.