The brick and mortar stores can't stay in business because of the occasional need to pick something up like that same day, especially when there is competition from own market AND from the likes of Walmart. Most businesses, the bread and butter of their revenues, are getting deliveries in bulk. Stores like Walmart, Target and similar can often cover the one time needs of stuff that may run out. It would probably be more profitable for a place like Staples to allow you to stop by their distribution warehouse in an emergency, or just allow same-day for a premium or X number of same day "emergency" drop offs as part of a contract.
With continued competition, these stores are going to get worse and worse and they eat away at each other while both are getting needled by the mega-store chains. I'd rather have one store that is maybe more expensive (I doubt it though, given the other secondary competition they face both physical and online) and has a decent selection, then two stores that are tiny and worthless.