Will it though? NZ would have to improve vastly, to be bluntly honest, for that to happen.
Fair play to the crowd, but it was their first Boxing Day test in a zillion years. If it's more regular and that kind of novelty wears off, will as many travel to watch them get belted?
That's not to say that they shouldn't get more, I firmly believe Test series should be more diverse than they are and NZ/Pakistan/Sri Lanka/Windies and even Afghanistan down the track should also get Boxing Day tests. But it's a relevant consideration I guess.