Eggs, eggs, eggs--America's answer to every breakfast question

 I've long wondered why we tend to assume that eggs = breakfast and breakfast = eggs. We cling to a the idea of eggs in the morning and seem to assume that the whole breakfast ritual would collapse without them. We scramble, fry, coddle and poach as if our lives depended on it. Is there something inherently matutinal about eggs? How did the egg get enshrined as the default, the national reflex for morning food? (N.B.: It's always a chicken egg, by the way, never duck, quail, turkey or goose.)

A wholly capricious Google search has me wandering through explanations that include medieval resistance to any morning meal at all, numerous 17th-century recommendations in favor of starting the day with solid proteins, our agrarian history, and a significant advertising push from the Beech-Nut company in the 1920s to accompany your morning bacon with eggs every day. The search, so far, is still deeply unsatisfying. Why the egg?

Browse through American menus, either online or in the wild, and you'll see I'm on to something.

Feel like a burrito? Maybe it has carne asada or chicken, rice, beans, onions, peppers and some kind of sauce. But throw a scrambled egg in there and magically it's a "breakfast burrito."

You're a burger person? Beef patty, maybe some cheese, possibly a tomato and some lettuce. With the addition of a fried egg and the probable subtraction of the lettuce and tomato, it's a "breakfast burger."

I spotted a country-fried steak offering on a menu that was served with a horse-choking amount of sawmill gravy, various fried-potato options and--you guessed--two eggs. That, my friend, s a coma in the making.

Throw a fried or scrambled egg on any sandwich from sea to shining sea and it becomes the "breakfast" version.

But I still don't understand why. (The tradition of protein in the morning? THAT I understand, especially in light of the agrarian history.) But why the egg specifically? Why not a legume of some sort, or a bit of cheese, or (in the higher-income echelons) meat? Is it because more farmers and many households had chickens as opposed to dairy cows and other large livestock? (In which case, why bacon--but that's another cognitive cul-de-sac for another day.)

This is no anti-egg screed, just curiosity. I bear eggs no ill will and I'll eat them sometimes. I bless (and chuckle at) the pretty feathered ladies who provide them and I know they're a useful matrix for gluing together bits of chopped meat and vegetables for a breakfast "scramble" and all its permutations--culinary duct tape, if you will. My bestie's adorable husband makes the best egg sandwiches on earth, with ham and cheese. My own darling mother--God rest her soul--used to feed me microwaved (fake poached) eggs with tons of butter, torn-up toast and a little salt when I felt bad or had a tough day. That concoction took the edge off of anything--sniffles, "female complaint," snarky teachers, bad boyfriends, you name it.)

But I still want to understand our totemic reverence for the egg, as opposed to other proteins, as the hallmark and necessity for a "real" breakfast.

Thoughts? (Also, hardboiled eggs seem to be allowed to run free and play at other meals--egg salad sandwiches, the quartered egg in a Nicoise, cobb or chef's salad, Scotch eggs . . . again, why?)