I'm surprised Kanban is only mentioned cursorily. Limiting work in progress is one of, if not the, point of Kanban.
Totally agree with your point, especially funny how author rediscovers that "Limiting work-in-progress is the tool every manager and leader needs to have in their tool belt. This is the one super power that over time will allow moving faster to the desired goal".
Why do literature review.
[1] Principle #6 – Visualize and limit WIP, reduce batch sizes, and manage queue lengths - https://www.scaledagileframework.com/visualize-and-limit-wip...
[2] Little’s Law - https://en.wikipedia.org/wiki/Little%27s_law