What is missing and what I should buy are different things. If my fridge has yogurt, bacon and some hamburgers, you might say "well, you are missing eggs". Except maybe I don't want eggs. I may be even allergic. Or maybe I like eggs but I'm in some low-protein diet for whatever reason.

The goal of a fridge is not to have literally everything, is to store everything you think you need for some days.

As for recipes, yes, that's more creative, but I guess I would just actively Google that (or even use an old fashioned recipe book!) if I were looking for original recipes. Of course, you can also ChatGPT it, but the direct fridge -> ChatGPT interaction is a bit weird because maybe I don't want original recipes or maybe I'm going to eat out.

So a hypothetical (?) app that sends me notifications about what recipes ChatGPT suggests by looking at my fridge wouldn't be very appealing unless you're always looking for new recipes. If you're mostly cooking ordinary things, continuous "You could cook X" would count as spam, much like a lot of people skip (or try to skip) ads on Youtube and ignore random "buy this at 70% discount" emails. And if you're that passionate about new recipes I guess you're probably interested in cooking and don't need the fridge to tell you what's missing.