Coupe was speaking to an audience of retailers, brands and other members of the grocery industry at the IGD Big Debate in London.
Speaking about changing expectations, he said: "Our customers no longer find it acceptable to order something today and have them delivered in two or three days' time. Our world has to adapt to that very broad range of customer demands."
Sainsbury’s last month completed its £1.4bn takeover of Argos owner Home Retail Group, a move that improved the supermarket’s ability to offer speedy delivery and click and collect services.
Coupe said the merged business would have an "unparalleled" offer among UK retailers in food and general merchandise, as well as financial services, thanks to the combination of Sainsbury’s Bank and Argos’s credit facility.
He also dismissed the idea that the two brands were not a good fit for each other, given their supposedly different market positions and consumer demographics. "I’ve heard this over and over again – but if you look at the hard data, around two-thirds of the UK population shop in Sainsbury’s, the same in Argos, and around 40% in both.
"So that shows that there’s an overlap but also an opportunity. The idea that two mass market brands do not work together is nonsensical."
Coupe was also clear that legacy retailers faced an unprecedented threat from insurgent businesses vying for parts of the consumer journey.
Asked about the threat of companies like Uber, which in June announced a partnership with Walmart in certain US cities to deliver groceries, he said: "It was inconceivable a few years ago to think that a taxi firm could be a competitor to Sainsbury’s, but it’s certainly a visible threat.
"The idea that someone is going to put themselves between you and your industry is a big thing – there’s whole industries that have been disrupted. We have to disintermediate ourselves before others do it for us."
Sainsbury’s recently launched Chop Chop, an app that can be used to arrange one-hour delivery by bike in select areas of London.