Everything you said is accurate, but that doesn't mean there isn't a place in the market for Blue Apron.
People are paying for convenience. Think of it like a house cleaning service. You don't NEED to hire someone to clean your house, but it makes your life a little easier and for some, that's worth it.
Except this is like buying a small package of cleaning utilities for one cleaning and then cleaning the house with it yourself. In your analogy, the cleaning service would be ordering food from a restaurant.
The utility here is very marginal, and there are alternatives that make your life even easier.
You need to understand that people do irrational things all the time but feel like they get a positive benefit from it. Meal kit delivery is easier than picking out recipes yourself and then buying ingredients yourself. It's certainly not easier than ordering takeout from a restaurant. But there's the "feel good factor" of doing the cooking yourself but removing some of the prep and decision-making. It's not all about utility; emotion factors in heavily sometimes.