Here is your regular reminder that it is still early days. Still just 8.5% of all retail sales in the US are conducted online.
Data and visualization via the Federal Reserve Bank of St. Louis and the U.S. Bureau of the Census:
E-commerce share halts but doesn’t decline in recessions. (gray areas) This makes sense: While the overall economy might be down, people still need to buy clothes etc. Doing this online allows for greater control by the customers over prices they ultimately pay and so on. (I’d wager that the growth of online retail’s share in the next recession (which hopefully will not happen anytime soon) will not halt but increase dramatically. Today’s robust e-commerce sector in the Western countries is far better equipped to adapt than brick-and-mortar retail. See also next point.)
With the talks on the current retail apocalypse happening in the US right now, ask yourself what will happen than e-commerce share reaches 15%, 20%, 30%. Scale effects and a house of cards.