> How many people who were living in the 1700s do you think sat around thinking life is a farce?
The name for this view of the universe is "absurdism". It was first espoused, as far as I can tell, when the discourse of Qohelet was recorded in the book of Ecclesiastes. So yes, they had it in the 1700's although perhaps not by that name.
> If you're working every day in a coal mine so you can feed your children otherwise they will go hungry, then you don't have these kind of thoughts.
This is almost the opposite of the truth. Those with careers that do not occupy their minds do not sit around with their brains idling and empty all day. They spend much of that time thinking about exactly this sort of thing.
Note, I didn't say "no people" thought this way. Just that very, very few people thought this way, which is absolutely accurate.
Unless you thought most people in the 1700s were sat around smoking cigarettes in cafes discussing the absurdism of life?
I suspect it to be far less rare than you think. Literally every human at some point in their life asks "What is the purpose of my existence?". They are then faced with some variation on "to be or not to be." It is not the exclusive domain of the idle and the educated, they're just the ones who write about it. It's a universal condition, and effects those without leisure equally. If that weren't true religion would not have been the driving force behind much of civilizations rise. Even the overworked and overwrought look for answers. Perhaps ESPECIALLY the overworked and overwrought. So maybe they did not sit about in cafe's discussing it, they mined coal while thinking it quietly to themselves or shouted it in crowded bars after work when they'd had a bit too much to drink.
Hell, I was a teenager working at Taco Bell when I first read Camus' "The Myth of Sisyphus". Well before that though many a bean burrito were handed out the window while I considered the absurdity of life. Perhaps my thinking wasn't as nuanced as it would later come to be, but the concepts occurred to me quite naturally.