As far as I'm aware, lightning was never used for any host device product line or use case that wasn't previously served by the 30 pin connector. So it clearly

As far as I'm aware, lightning was never used for any host device product line or use case that wasn't previously served by the 30 pin connector. So it clearly wasn't created with an intent to allow a broader range of devices to share it (or else they simply failed at achieving that). It covered the same use cases across the same product lines as the thing it replaced with no expansion upon that. Therefore there was never any "ongoing savings" by bringing together a greater range of use cases compared to the alternative.