Hey, I co-founded Instacart and can offer some thoughts on this.
In most cases we are helping retailers create a new delivery experience for their customers, not replacing one that exists. It's actually quite complicated to operate our business and there are economies of scale that retailers benefit from by being part of a marketplace.
Also, when we talk to our customers about why they use Instacart, many of them do need groceries urgently, which is one of the reasons they use Instacart over alternatives. Most orders are delivered within 1-3 hours of being placed.
In most cases we are helping retailers create a new delivery experience for their customers, not replacing one that exists. It's actually quite complicated to operate our business and there are economies of scale that retailers benefit from by being part of a marketplace.
Also, when we talk to our customers about why they use Instacart, many of them do need groceries urgently, which is one of the reasons they use Instacart over alternatives. Most orders are delivered within 1-3 hours of being placed.