There is no doubt that customers would love to have the stuff they buy delivered to them on the same day---for free! But are they willing to pay for it? More pertinently, are they willing to pay as much as it actually costs to deliver? Here's one random reference for estimating how much it might cost to deliver: an old article from WSJ suggests that it costs $9.44 to deliver pizza. Of course economies of scale, better algorithms, etc. have probably brought that cost down, but I don't think there's a sufficient market of people willing to pay actual costs of delivery, not yet anyway.Companies like Google, Amazon, eBay, and Uber are operating and expanding services that allow shoppers to order something online and have it that same day, without ever leaving home.If they manage it, despite the expense and complexities involved in delivering over the "last mile," these companies will grow e-commerce's customer base (as well as its share of retail dollars), and siphon off one of offline retail's last real competitive advantages.
And yet, same-day delivery will continue to grow, as the companies doing this will continue to absorb losses. At some point the market will have to correct itself, I suppose.