You got it right! Since each user is paying less per chapter read, you need more subscribers on the service to surpass the revenue that would have been received with a-la-carte only. And there is a huge opportunity to get more subscribers paying to read than there are people paying under the traditional a-la-carte structure due to the much lower barrier to entry. This is exactly how Crunchyroll pushed the anime industry forward where physical sales are mostly downstream from digital subscription services.