Genuine question. I was a kid in the 80s and 90s so perhaps I was not privy to these sorts of conversations, but I rarely recall people complaining. Today, it seems like the majority of conversations I am in or read on social media revolve around some sort of complaint. My hypotheses:
(a) People complain the same amount today as in the past, but now everyone has a voice / platform to project their complaints far beyond what they could in the past.
(b) Because everyone has a platform to project their complaints, and because everyone therefore exposed to more complaints, everyone complains a lot more now. This is sort of akin to the research that shows dissatisfied customers tell 5X the number of people about their experience relative to satisfied customers.
I think this trend is definitely more pronounced on social media, as even well-intentioned posts degrade into a complaint-fest. Examples include most discussions on NextDoor, Facebook, LetsRun, Twitter, etc.