Where the value falls down is in how much of a time sink it is. These meals take a fair amount of prep, and in exchange for all that time you only get two meals.
When I cook on my own I usually batch enough to have at least another 2-3 meals worth of leftovers. If they set it up as a channel for weekly meal prep rather than 3 fun new recipes to try we'd be much more inclined to stick with it, but as it is it's just too much work for busy people to do every week.
If they provided larger meal sizes it would probably come closer. They'd be able to provide you one meal's type of food (less variety, fewer things to measure, and fewer types of ingredients = easier supply chain management) and you could get 5 or so meals out of one cooking session's worth of prep.
It probably still wouldn't come down to $7. But I assume there are people more willing to pay than me out there who would be happy with it.
But Blue Apron, as it is now, isn't cheaper or easier than what I do now and it's a nightmare of wasted packaging.
Three fancy-ish meals during a typical week tends to seem like a bit much. I'm also cooking for one at least some of the time. On the one hand this usually gives me leftovers. On the other hand, I don't have the portion control I'd have if I bought the ingredients in the store and not all their recipes lend themselves well to leftovers.
On the other hand, I look at some of the services that more explicitly try to simplify. Those that do more of the pre-prep make sense to me but I also see recipes that make me go: "Umm, I could grab the three ingredients for that in 5 minutes at the store."
All that said, I'll probably give these things a try again when I have some periods at home. I don't actually have a good grocery delivery option where I live so it's easier to justify these services on that basis given that they can cut out a visit to the store.