One thing I don't see very often in connection with Agile is the reasons pre-Agile project management approaches failed: Replanning a resource-leveled critical

One thing I don't see very often in connection with Agile is the reasons pre-Agile project management approaches failed: Replanning a resource-leveled critical path analysis takes way too much time and effort for little benefit in the context of most kinds of software development projects. That, in turn, points toward incremental assignment of people to tasks as a key difference. There are of course many other differences, but exactly zero Scrum certification training courses even come close to mentioning stuff like this. "Cargo cult" is the inevitable outcome of not knowing anything about why one should do Agile for software development projects.