Agreed except for the part about refactoring: > if management believes them and gives them a free hand, then sprint velocity goes down by 80% and bug counts go

Agreed except for the part about refactoring: > if management believes them and gives them a free hand, then sprint velocity goes down by 80% and bug counts go up by 90% as stuff randomly breaks in the refactor. 5x less velocity and 10x bugs is not the result of any sane refactor. Anywhere close to this would indicate that either the devs massively underestimated the complexity of the job or their own competence, or something else in the process is broken, such as letting the senior estimate and the junior implement the change. The vast majority of refactorings are in my experience non-events, simply because I'm by now used to working with thoroughly tested systems.