They don’t have to hire you every two weeks but they are paying for you and do have to decide how to allocate your time and plan various projects with interlocking dependencies. How can they do that without even a rough idea of how many people it takes for how long to accomplish anything? You are, in effect, still asking them to write you a blank check to accomplish something when they might want to change gears if apprised of how difficult it is.
If you go way back up in this thread the reason given for Scrum being bad is it features estimation, which is useless because it's inaccurate, so telling me that systems other than Scrum feature estimation is not a rebuttal.
