When techniques are misused they are misused. The fact that there are bad project managers that don't know how to use a schedule are just as bad as the crappy

When techniques are misused they are misused. The fact that there are bad project managers that don't know how to use a schedule are just as bad as the crappy "scrum masters" and "product managers" that don't know what "agile" actually means. A good project manager will be continuously revising their schedule, based on updated estimates on the tasks. They will know how to compare it to, and update, the baseline. Not sure what you mean specifically by "bus number" but happy to learn. The GANTT chart is just a format of displaying tasks, their resources and dependencies. The actual DAG is a pure data structure. If you put a confidence level indication on the estimates, a good project management tool will also be able to do analysis of the critical path (ie the length in time of the longest path) with a level of confidence on earliest/latest predicted end dates. People think that nonsense like "t-shirt sizing" actually means anything other than "wild-assed guess" or that burndown charts are useful when adjusting future estimates. All techniques to avoid doing the hard work of scheduling and project management.