The fact that nobody (or very, very few airlines) has ordered it is telling. I believe the initial capital cost of the A319 NEO is high (more expensive than a new A220-300) and it is difficult to spread costs across fewer seats than found in the bigger A320 NEO. From a CASM standpoint, I believe the A220-300 still beats the A319 NEO by a good margin. Nobody is ordering it beyond a few VIP/Bizjet versions.