So the economy has been canceled, and no one can afford to eat anything other than canned soup and the occasional box of macaroni and cheese. But you can cheer yourself up with the knowledge that some day, people in fancy restaurants will pay top dollar for the food found in the average dorm room or trailer park.
How do we know? Because many foods that we now consider to be classy and/or expensive were at one point the foods that meant Timmy probably wasn't getting that new foot for Christmas. So in a couple of generations we'll see who is laughing about our tower of Noodle Cups.
It's no surprise that lobster didn't use to have much of a reputation. It is, literally, a sea insect. The lobster belongs to the same animal group as both the spider and the common bug, which should be your first clue. They were initially thought of as giant hassles that got in the way when fishermen were fishing for, you know, fish. You know in Forrest Gump when they first pulled up their nets and a bunch of junk fell out? The lobsters were the equivalent of that toilet seat.
The lobsters they presumably found crawling around the bottom of the fish bucket were originally what fishermen gave to their indentured servants to eat. People were so averse to eating it that they ground it up and used it as fertilizer, instead. Being seen as someone who had to eat lobster was something you generally didn't tell anyone until at least the third date.
British POWs during the Revolutionary War supposedly revolted over being fed too much lobster, after having apparently developed culinary Stockholm Syndrome from British food. Some states actually had laws against feeding lobster to inmates more then a few times a week, on the grounds of cruel and unusual punishment, as it was seen as the equivalent of eating rats.
Then How Did it Get So Fancy?
Somebody went and invented the railroad. Soon, rich people from the middle of the country--who were painfully unaware of what was cool--were tricked into buying the sea insects. But after tasting them, they realized that they must have discovered the long lost gatekeeper for butter.
Ironically, lobster is now a commonly requested food for prisoners receiving a last meal before execution, where as back in the day who knows how many last meal requests were something to the effect of, "Anything but more freakin' lobster, ya cruel bastards!"
The oyster is a cousin of the snail, nature's glue stick. Oysters also hang out with, and look like, rocks; further proof that giving in to peer pressure is an important survival technique.
Furthermore, in the olden days, eating one required you to be really committed to the task of eating something that looked like a rock. If you succeeded in prying them off of rocks without just giving up and eating a baby, you still had to get that sucker open, because they have to be eaten when they're as close to alive as possible. This involves cracking open a shell that is the animal kingdom's equivalent of a medieval chastity belt.
Eating one you've found to be already even a little bit open (and therefore dead) is pretty much booking a two-night stay at the nearest bathroom, where you'll have plenty of time to wonder why it was you thought that it'd be a good idea to eat a rock.
So you can see why the abundance of oysters in the 19th century led to their being mostly eaten by the working poor in the U.S. and the U.K. (also, they're not very nutritious). Dickens even mentions them derisively in The Pickwick Papers, making them certified riff-raff food even in a literary universe where people are willing to start shit over gruel.
Then How Did It Get So Fancy?
The industrial age brought a population boom and many, many oysters were eaten. Coupled with the kind of pollution you normally only see in dystopian 80s movies about 1999, many of the oysters were killed off, driving up price and demand, and therefore catching the interest of rich people.
To fix this problem, foreign oysters were brought in to replenish the population. Unfortunately, 19th century medical science was still in its Flintstone's car stage, and nobody thought to point out that the local and foreign oysters might carry diseases that the other might not be immune to, leading to tons of oysters eventually becoming rocks for real.
Thus oysters were made permanently scarce and pricey, and as Beanie Babies proved, rich people will spend money on anything if doing so means that you can't have it.
Foie gras goes back to ancient Egyptian times, when man discovered that the liver of a really, really fattened goose was a lovely primeval combination of tasty and gross. Getting the goose to prime hedonistic conditions requires feeding it to the point of the liver growing to 10 times its normal size. Which means that you can continue eating those Hot Pockets secure in the knowledge that at least when you die, at least part of you will be great on toast.
The dish almost died out during the Middle Ages, when most people were chiefly concerned with trying to stay away from the burning piles of plague victims. Geese were probably able to stop having nightmares about waking up in bathtubs full of ice.
But the Jews, with their constant address changes (due to constantly being banished from one country after another), needed a source of cheap, kosher fat. It was kind of a disgusting necessity, and the first written document about foie gras is actually written by a Jewish religious leader admonishing his people for how gross the whole thing is.
In fact, this advanced-degree having lady goes so far as to postulate that bans on foie gras are anti-Semitic because they attack a necessity of medieval peasant Jewish cuisine. However, this is assuming that most people in favor of a ban on foie gras (now usually made with duck) express an argument more complex then "Hey, I remember thinking that ducks were cute last Easter, which was the last time before now that I have thought about them."
"Aww, aren't you temporarily sympathetic!"
Then How Did It Get So Fancy?
The Renaissance brought back interest in things other then just conquering people, which meant that royals were getting back to the business of conquering their arteries. People traveled to the Jewish ghettos in Rome to buy lobes of foie gras; these lobes found their way into the kitchens of royals, who were getting frustrated waiting for the deep-fried Twinkie to be invented.
Then, word got around that foie gras was off-putting and awesome, the French started putting it in everything and charging $10 an ounce.