How so? Sure, a few drivers would be replaced. However, the last-mile driver is also taking care of the doorstep delivery. Even if you replace the driver, someone needs to finish the delivery/get signature/whatever.
Self-pickup/Drop-off wall of drop boxes ... mounted on a self driving truck that sends you sms 10 minutes before showing up, or better yet lets you schedule your own time and place.
Shit, with retarded patent system in US someone is already patenting this as you read my post.
There is no battery problem for truck-to-door. The truck charges between deliveries and spare swap-in packs pick up any slack if the duty cycle is too high.
I'm trying to think what you'd use compressed air for here, and the only thing I'm coming up with is some sort of parcel cannon, which while awesome does seem to have a few issues.