The top will fall. The precession (the way the axis of spin itself revolves) means it will fall. I don't know whether people don't understand the physics or just didn't see it, but the top is beginning to fall. It is not necessary to see it actually hit the table to know this.
Well sure, being that it's not a CG effect, it will obviously show physical signs of eventually
falling over like any real spinning top would.
But the question is whether that was the intention by Nolan, or whether we're supposed to suspend disbelief (like in any scifi movie using practical effects) and accept that it actually DOES go on spinning forever.