Digital bottlenecks are not often solved with only digital means.
Like Scott Galloway points out in this brilliant presentation about the masters of digital universe, the Amazon´s Achilles heel is the shipping:
Their shipping costs are exploding at 40% and shipping fees and transportation costs are over 9 billion. Free shipping has been one of the main reasons why people choose Amazon and what makes them unique. There is no immediate digital solution for shipping (as long as there are physical products). Drones are quite long shot to solve that challenge*.
New digital opportunities might reveal old challenges.
*Interestingly, the unsexy solutions might be the most sustainable. Click & collect is hugely popular, albeit archaic way for eCommerce and traditional retailers might find innovative ways to use their store network for flexible warehousing.