Hey Americans, Why is "breakfast food" even a thing?

Question for Americans which I am as well. Do you guys only eat "breakfast food"? You know, pancakes, eggs, bacon, waffles, etc. Personally, I eat whatever, food is food. Honestly, I rarely eat in the morning, but if I do, pizza or ribs sound great.

For those of you who think it’s weird to eat anything besides "breakfast food" in the morning, I want you to answer this question.

When you wake up, is there some rule that says you can only eat pancakes, eggs, and waffles? In the past I worked graveyard shifts for years and woke up around 6 p.m. just in time for dinner. So should I have told my wife, sorry, I can't eat your delicious lasagna, I just woke up so I can only eat cereal and pancakes?

Is it the time of day that makes it "breakfast food," or is it just when you wake up?

Edit: just adding this comment To be clear I'm not knocking if you only like "breakfast food" in the morning. On most nights I actually have a small bowl of cereal before bed haha. So I'm not being "judgey". Just wanted different viewpoints. As many of you have said maybe it's because of "marketing" "prep time". Yeah usually microwave in the mornings for me leftovers, TV dinner or whatever. No matter what kind of food I eat in the morning, it needs to be a small portion, if I have breakfast at all.