I stopped getting worked up about what Trump says a long time ago. The further away from a date at which something is to happen, the more likely he is just blustering...or just as likely, maneuvering himself and others towards the final result he wants (which may or may not be what he announces). I don't think he announces what he wants ahead of time to force everyone to that precise place necessarily. I think he announces "what he wants," say, 3 months ahead of time, because he thinks that is what is best to announce at that particular time (3 months early) to get people to where he really wants them to be 3 months later (which may or may not be what he announced).
It is typical CEO behavior. It is frustrating as an underling to hear your CEO announce goals that may not be achievable, but they do it all the time to force you to extend yourself as much as possible in that direction. The CEO may not actually know what is achievable when he announces goals, but he does know that if he underestimates what is possible, people will often do something less than what is possible. Not knowing whether he can get $10M or $14M from a project, he may demand revenue of $16M from the project (which may be totally unreasonable), but that may get the project closer to $14M than if he had demanded a very reasonable, middle of the road $12M. He's not concerned with estimating correctly; he's concerned with motivating people. Sure, if the media followed corporate decisions like they do politics, the media would rip the CEO a new one for "predicting" $16M, but it may be the right thing to say to get as close to $14M as possible. He can be "wrong" while doing the correct thing for the company.