We have a long history of attempting to communicate the uncertainty of outcomes to non-technical stakeholders. We speak in delivery probabilities, not certainty. It can be frustrating to those who don't understand, but software development is not cookie cutter...
One of the bigger problems we've seen in many companies moving to agile development is the fact that the people leading the change are typically **not** currently developers. Many took classes on "Agile" to become "Certified", but the real world examples people need to translate their current processes to delivering with more agility rarely come from books...
Accelerating delivery is a key strategic initiative for any company wishing to remain relevant with today's rate of change. When teams start the journey from "artisanal development" to continuous delivery, they rarely understand the level of improvement they will achieve...