Good question! Most organizations, especially the larger ones, are set up to operate on an annual cycle. Project plans, staffing, budgeting, progress reporting, and performance reviews all follow this unstated assumption — and all of these things impact the design and execution of products and services. And it really bears no relationship to the real world. It’s kind of crazy when you step back and think about it; but it’s so deeply ingrained that most of us don’t even realize we’re making that assumption.
This is the ultimate source of most of the “that’s nice but we can’t do that here” comments that I hear. To become more (lower-case “a”) agile, companies need to call this out and rethink their processes; and it needs to be done at every level, and in every part of the business.