The reason the new adapter (which lets you use old accessories with the new phone) is so expensive is not, because Apple wanted to inflate its quarterly revenue but because the old adapter is analog and the new one is digital, and so the adapter includes a tiny analog-to-digital converter, and those who have any experience with such things knows that they are typically very expensive.
Lightning I/O has built-in support to host USB devices, which could lead to more fully-featured accessories than previously possible. Think keyboards, digital cameras, MIDI interfaces, mics and other USB-based gear