Let me try to be a bit more clear. There may not be any wall if he leaves office, there may not be any wall if he stays in office. In other words, there may not be any wall in spite of what he promised.
Sure, and a ten mile wide asteroid may not hit us and exterminate all life on earth.
You literally have said nothing. Unless, of course, you're implying that President Trump may break his promise to build the wall. Is that what you're saying?