Have you considered the possibility this is not a result of incompetence, but intentional? If these things are never clearly communicated and, more importantly, put in writing, management can just reframe what was agreed upon as best suits them later to deflect any blame if things go sideways. This is a perfectly rational move, since they hold all the power to do so.

I think a lot of what is wrong with this discussion is that people implicitly assume management is honest and communicates openly and sincerely. This is sadly only true in a small fraction of cases, likely because the incentives point squarely in the opposite direction: those who judge the game are always better off cheating.