I'm really wondering in which world the product managers are living in. What is the goal of a roadmap ? This article doesn't even touch a point on it. The goal is : In any company there are people who want to have an answer to the question "what comes next on your product?". Those people can be any of: CSM to prepare a presentation for customers, bored customer who want to talk to CSM, Sales people who want to impres…
You will be a disliked product manager if you continually tell people what they want to hear, but never deliver on it.
Rather, tell (read: persuade) people what they need to hear. Your job as a product manager is to negotiate and reconcile high-level plans and low-level execution.