Alright, now let's factor in the material and labor cost of that.
You got a pan to cook that stuff in? An oven? Gas or electricity to run it?
Actually, let's back it up: do you have a refrigerator to put that food in? Do you have reliable transportation to a grocery store that sells these items?
Should we get into the time it takes? You might literally not have that time if you're working two jobs or juggling childcare.
Now, I know what you're thinking, "Of course you have pans, ovens, and fridges!" But... a lot of people literally don't. And it can be really difficult to scrape together the money for some of those items when you need to eat. Tell me, if you're hungry and you have $10 for the week, what are you going to buy: food or a pan?
I'm very fortunate. I have all kinds of cookware. I have reliable transportation to a grocery store. I actually enjoy cooking and have enough education on the subject to do that without ruining the food/can even make it taste pretty damn good. Even with that, I don't have a clue how to prep a whole chicken at the moment. I'm sure I could learn... but I'm not working two grueling jobs or taking care of kids.
The incredibly small amount of people you're describing that literally don't have any kitchenware or 10 minutes to make and eat a sandwhich for lunch every day aren't going to have the time to go eat out 12 times a week or spend 250 on expensive junk food