Coase’s math assumes that the intervals between price changes approach zero, but every state change (such as the ebook price updates) is an informational bit erasure or write event. In a real market there is a cost that is > 0 for any price change (landauer floor). One can not assume that there is "free" energy in the system to find the optimal price.

Anyone writing books (or a "firm in coses math) needs to persist, aka they need to keep things like consumers understanding of their quality and pricing. If they drop prices to nothing they have consumers learn that. Consumers that try to wait forever in an "idle" state make no purchases and are not part of the ecosystem. Only consumer that don't wait forever matter. aka if they are looking at your ebook and don't buy they will rapidly buy a different ebook because they cannot wait for infinite time. aka if you teach your customers to wait they wont actually wait for you, but will simply switch to something else.

This is a control-and-feedback problem. Coase Conjecture fails because it assumes that you can have a system that persists without a governor. The two real world explanations correspond to the two ways you can introduce a governor.