My interpretation is that the point is that it is not a guarantee that adding more inception layers will help. It might increase the performance, but it might also decrease it. In other words the way the question is phrased, it is asserting that it always helps. That is false, because there’s essentially nothing in DL that you can say that about (that it is always guaranteed to help). Everything is situational: even if it helps in most cases, there will be some outlier cases where it doesn’t.