When getting to multi-level complexity like your example projects are, why wouldn't you use a solution which can handle more complexity such as MS Project?
Tasks in any project would easily go into 3+ levels of complexity, depending on how you'd structure your tasks.More often than that, the less structured the tasks, the more difficult it is to remember, track, and prioritize them. If there's not a need for this, task management solutions such as Asana would not have the feature to append a list of subtasks to a subtask indefinitely. Microsoft project is great for handling large scale projects but you'd need to deal with the complexity that comes with it. Quire wish to address the need for task hierarchy without making a task management solution difficult to use.