They do so entirely based on past shopping history.

Currently the only annoyance is logging in once a week to check if there's any adjustments we'd like to make. But it's good enough that if I don't feel like it, I'll just take my chances (you can also add "always include X" and "never automatically add Y" rules, which is part of the reason why that works...) and most of the time I get what we need.

I never want to go back to putting together my own shopping list from scratch.

This is how I want these type of services to work. I don't want to have to talk to them. 99% of the time, I'd prefer them to be invisible to me, and make things that used to be an annoyance just disappear.

But the one way it could be better would be to make that one last interaction disappear more often: Not having to log in to make changes. Being able to just say out in the air that I want to add eggs, would be great, and in that case I'd want it added based on past preferences: If I've bought eggs before, and I'm not specifying, just add the quantity and brand I usually order. If an alternative I've also ordered is cheaper or on offer, ask for confirmation if I'd be happy with that instead. If I haven't bought eggs before, pick a brand based on my past overall purchase history, and ask for confirmation, or simply add some - if I'm asking to "add eggs" rather than "please recommend me some eggs for my grocery shopping", I probably don't care.