These points are very wise and correct. Yet, is it possible that situations might occur that don't fall into these situations? For instance, a hardware failure or a third-party service failure, or a common process is mis-applied and needs to be reversed. There could be a vast number of potential scenarios that are neither bugs nor novel events for which playbooks could be authored. There is non-trivial value to be gained in making it easy for an operational team to handle such events, particularly when events that do recur have their handling codified.
You are, of course, absolutely correct to note that many events either will not recur or cannot be anticipated. Yet, might there also be value to be gained by recognizing that there are events outside these categories that can be anticipated and planned for?
For any incident that happens, I'm going to — if at all possible — fix it in code s.t. it doesn't happen again, ever. There is no playbook: the bug is fixed, outright.
That only leaves novel incidents, for which a playbook cannot exist by definition. Had I thought to write a playbook, I would have just fixed the code.
(I am not saying that playbooks can't exist in isolated cases, either, but in the general case of "system is no longer functioning according to specification", you cannot write a playbook for every unknown, since you quite simply can't predict the myriad of ways a system might fail.)