I think flying drones for home delivery will be the new flying car. I think autonomous road vehicle is the future for cities with an attempt to deliver to the home and then to a central pick up.
Reason is money. UPS or the USPS can do it if Amazon and Walmart don't beat them first. Salaries and benefits are the biggest slice of the pie for expenses.
Are automated ground based vehicles really going to out perform automated flight based ones?
I can see that for large packages (~50% of current parcel delivery?) but that still leaves all standard envelope based mail and smaller package. Such as books by Amazon or the very broad group of various daily products people would START purchasing online if they could get same day delivery.
If we look merely at how things work now - yes - I believe what you're saying makes the most sense. Because it's merely a big optimization of the current systems.
But I believe this downplays the innovation that very fast same-day delivery of packages (within a few hours even) that drones could provide. It would seriously expand the scope of services businesses like UPS and Fedex can provide.
Suddenly pharmacies, drug dealers, restaurants, local bakeries, convenience stores, gas stations, liquor/wine stores, etc, etc have a new retail venue.
Why stop at the busy gas station to fill your cars tank before the daily commute when you can wake up to a prepaid jerry can in your drone box?
I'd bet the answer will likely be a combination of both with a much higher volume in the drone delivery side.
Reason is money. UPS or the USPS can do it if Amazon and Walmart don't beat them first. Salaries and benefits are the biggest slice of the pie for expenses.