Amazon.com’s competitive advantage over regular retail has typically been around good prices with the thing you are looking for being available. In essence, they are an online, extreme extension of the big box store.
The downside has been that if you want it now, you have to either pay extra for expedited shipping, or get it somewhere else.
Meanwhile, retailers have been attacking Amazon’s price advantage by working hard to put them in a position where they have to collect local sales taxes, leading to a number of court cases plus Amazon actually pulling their presence OUT of states to avoid having economic nexus.
Now Amazon has reversed this trend, and is starting to build very local distribution centers, promising, not next day delivery, but same day delivery – as in order it today, get it today.
The analysts out there are all saying this is the “death of retail” – assuming, I suppose, that although Amazon can change its strategy, brick-and-mortar retailers are, somehow, frozen in theirs. “Death of retail” really means “We analysts, while certainly not admitting we never saw this coming, can’t think of how we would respond.”
Ultimately someone will figure it out.
But I digress.
The point is this:
Short lead times AND high variety of offering AND good prices are what customers want, and that is what anyone in the business of fulfilling customer needs should be striving for.
The ultimate transaction is “I’d like one of these.” followed by “Here you go.”
Just because you can’t figure it out doesn’t mean others aren’t trying to.
Where does this ultimately lead?
This video speculates what would will happen when Amazon figures out how to deliver what you order the day before you order it. Enjoy. 
Don’t forget the power of trust. With Amazon, you can instantly see reviews on the item, and know that you’ll be able to return it with no hassle. Big boxes should get product review kiosks set up on their aisles if they want to continue to compete with Amazon. And they may want to consider going to a showroom style to reduce their footprint and inventory. They have to find the things Amazon can’t compete with–touching and holding a product in your hand.