We've all been there - leadership routinely pushes back the launch days or weeks before a big launch. How do you address this with leadership?

You have to articulate the cost. And specifically the cost to the business, not just the cost to your department.

For the most part, I cant say I've worked for many leaders that would value the human element (wasted time on your part) over the business value to a last minute shift to a launch (potentially because of alignment to another launch/bundle or product readiness, etc.). While there is an opportunity cost in terms of what you cant get to because youre still focused on the launch that could have been out the door, realistically speaking, you might be met with a response of .. "well its short term, you'll just have to do extra for this window of time". So focus on the opportunity cost to that it creates to the product -- we cant develop the next feature because we're still working on this one, our time to revenue generation is longer because we dont have this feature to help close deals, etc.

We had a launch recently where the launch date moved 6 times within 2 months. The cost in this case was that because of other features rolling out in parallel, it was a lot of wasted eng effort to keep the product ready. What i mean by that is that our process at that time was that if we had two teams launching new features at the same time, each launch team was responsible to not break features already live in production, but features that were also in the queue to be launched were the responsibility of that individual launch team. So because our launch date shifted, we couldnt ship the fast follow features we had in the queue because of the tech debt created by not letting the team launch the feature at the original date, and as such shifting the responsibility for product maintenance to the other teams launching other new features.