I like ordering groceries online, but I think the idea of
instant grocery shopping is flawed.
1) You're depending on & supporting an oppressed segment of the labor force (people who need multiple jobs to make ends meet, because no 'gig economy' startup pays a living wage), 2) You're fighting with "surges" of use and paying wildly varying prices, with wildly varying levels of service, 3) You don't even get the items you're looking for half the time (in my experience), 4) It's more expensive!, 5) you don't actually need groceries delivered to you instantly.
Since COVID-19 I have switched to buying from local businesses and getting food from Co-ops and farm shares (and growing my own). I can schedule regular deliveries of produce to my door in bulk (in reusable containers), which not only reduces waste, it actually helps me plan my week/month better, I still get all the things I wanted, the price is fair, and I'm helping local farms and businesses.
I'm pretty sure the reason most people don't do this is that they're lazy, selfish, greedy and entitled. My evidence is the last two weekends I've ventured out into the world to look at apartments to rent, with the occasional jaunt to a hiking trail. I found virtually nobody was wearing a mask or socially distancing, unless they were forced to by a greeter in front of a business like a grocery store (many customers were trying to walk in without a mask, and thankfully were rebuffed). Many probably could have ordered online the same way I did, but would rather the immediacy of 'do it yourself' - even during a pandemic.
Sadly it's the poorest and most vulnerable people that need grocery delivery the most, because they have the hardest time getting to a store. A poor person in a food desert may need to spend over two hours round trip on transportation in order to get food, and an elderly person may just not be mobile enough. I doubt we would ever fund a public delivery service for them (though in theory the postal service could).