Manna has been a reality for more than a decade. Practically the entire warehousing industry uses a fully automated voice system that's almost exactly as Brain describes. An increasing number of retailers are using headset communication with both human and automated elements - your headset receives voice messages from co-workers, managers and automated systems.
Voice picking is already being rapidly supplanted by human-less (robotics) processes. If the cost of implementation for these systems ever dips low enough then a terrible number of warehouse jobs are going to disappear nearly overnight.
That's how the previous generation of Amazon warehouses worked, with pickers wearing headgear that told them where to go. Now that part is done with robots, which bring the shelves to the pickers.
Manna coming to life (https://marshallbrain.com/manna)