Someone made a silly mistake in the booking, but either nobody noticed, or couldn't be bothered to correct it, or dared not be the one to tell Trump the mistake had been made. So the President (staff? apparently not him) gives a final press conference in the parking lot of a suburban store. It would be like watching the Emperor of Japan surrender in a dinghy because somebody brought the wrong Missouri.
Unforced error. Abandonment of dignity. Refusal to acknowledge the situation. Hallmarks of the administration.
(News accuracy notice: while it appears to have been an official press conference only Guiliani was actually there and not Trump himself)