At the heart of agile software development is the first enumerated principle from the Manifesto for Agile Software Development:
Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
We have fallen into a pattern of not having demonstrable software when an increment concludes. There are heavy sighs when the question arises of what is there to show at product review.
I propose remedying this unvirtuous cycle by trying an experiment. This radical idea is to focus on The Most Important Thing. We spend time bandying about number of developers and weeks. We don't spend much attention to what is Important. If something is important we should attack it with virgor and defer new work until completing Important Thing.
This approach ensures that things get completed. Time spent 'in-progress' for the Epic is minimal. We've all see the task/story that sits at 80% done for 9