> If there is as much money to be made as Instacart's valuation implies, then it's just a matter of time until the big chains, at least, start offering their own online shopping.

They already do. We sometimes use personal shopping at Whole foods, it costs like $15. You drive up and pick up the groceries. Super easy. Another smaller chain store, for $20, they will shop and deliver to your door.

While great in terms of saving time, the problem is that you sometimes dont get exactly the item you would have picked nor get the option to pick up extra items or things on sale.