It seems pretty unfair, when you think about it. Project Management demands certainty, but it doesn’t give you any. You have to bring your own.
My earliest experiences with project managers in a large corporation, decades ago, included listening to a raft of complaints about this. Those project managers often were the target of what really were attempted cons, by their own managers.
Boss: “When will the project be finished?”
Project Manager: “It’s ‘way too early to tell. We have to get a lot of quotes and estimates before we have any idea of how long it will take.”
Boss: “Well, how about just a rough idea? I won’t hold you to it.”
Baloney. If the project manager should mistakenly breathe anything, however circumscribed and conditional, that could be interpreted as a number or a date, it instantly became carved in granite.
At least, that’s how the story went, and I have heard it countless times. Still do, now and then.