It's a matter of perspective. We have a culture that largely puts business interests above independent peoples interests. If you agree with this then it makes complete sense that it's better for the company because that employee might have been kept and we want to keep them stable. If we warn them, they might become a flight risk and we might not need to cut them. Information asymmetry is our friend so let's give them only the information that's beneficial to us.

If on the other hand you take the perspective of supporting a bottom up independent worker interests above a business's (I fall in this category), then your point is quite valid. Information asymmetry here put me in a terrible situation, if you would have told me earlier, I might have made different decisions. That might not include leaving, but it might have included tidying up my resume and prepping for interviews, just-in-case. Maybe I follow through or maybe I just keep some backups lined up in case things go south. Some may just pass the risk back to the business and jump ship since they assume they have better odds doing this and may even get a promotion.

Personally I don't believe any business leadership's words, I skim financials, I watch movements in the laborforce especially around management, I look at markets and make my own interpretation. I assume they're providing intentional incomplete information to their advantage and try to infer reality from that combined with the other data sources. Businesses are not your friends and will lie to you to their advantage above all else. I'm not a subscriber to Hanlon's razor when it comes to self-interest. What can typically be attributed to self-interest should be considered above incompetence, especially when looking at something as strategic and methodical as a modern business structure that have countless meetings to sit around and discuss and analyze these sorts of things or contract specialized skilled services in these domains.