There is a difference between not knowing what I need for an API next week and not knowing (vaguely) what I need for the business. My backlog stretches out abo

There is a difference between not knowing what I need for an API next week and not knowing (vaguely) what I need for the business. My backlog stretches out about 4 months at the moment, but I don't do technical design until much, much later. But as a sibling post rightly points out, not all of the stories on my backlog are going to get done. 4 months is a long time and the business is hopefully gathering more and more data about what it needs. Frequently opportunities arise that overtake what I have in my backlog. Since I always have more in my backlog than I can actually do, that means that the stuff on the bottom drops off. If I were to estimate, I would say that about 1/3 of my 4 month backlog is practically 100%. It drops off to 0% by the end.