Lobster was once for prisoners and slaves or a poor mans food, while nowadays it's almost exactly the opposite. It'll be hard to find a prisoner or slave that gets to eat lobster.
Oysters were poor people food in the same era, and like now, many people ate them raw. It has less to do with culinary trends and much more to do with the relative productivity of the lobster fishery. (In recent years, the lobster fishery has been really productive, but prices have been pretty sticky[0].)
Mark Kurlansky's The Big Oyster has some great primary source research on the social status of eating shellfish through the years.
At the time when lobsters were fed to prisoners, they hadn’t yet figured out the boiling-them-alive trick, which is supposedly how you get lobster to taste good. I don’t know anything about oysters though.
Boiling lobster (and other things) alive is more about preventing food poisoning as bacteria appears quickly as soon as it's dead. You could kill a lobster right before cooking it (not boiled alive) and have the same flavor + reducing health risks.
It's not ironic. Agricultural methods have changed over the millennia and as a result the relative price of many foods has gone way down. See also white rice.
I'm not aware that quinoa is expensive. Some rich yuppies have the time for following lame food/health/lifestyle trends. However, doing that is lame at any income level. A proper bro dude will never eat yogurts sprinkled with acai berries and quinoa or whatever crap.
poor people use wheat etc.