Not counting the costs of the time and convenience needed to transform the raw materials into something edible (and discounting the fact that some people simple do not know how to do it) is what singles your post as tendentious.

I don't know what you want to prove; it is definitely not that it would be cheaper to eat at home - for this to happen, someone has to cook. And this someone could, perhaps, think that he/she has better things to do with their time.