Pretty much my experience. My pre-teen childhood was the 1970s. My parents had dinner parties or cocktail parties at home at least a few times a year, and so did most of their friends. We often had a sitter for the night while they went to these gatherings. Some time towards the end of the decade, and certainly in the 1980s, this pretty much stopped. I asked about it once and my mother said that hosting these gatherings was a lot of work and fewer and fewer of their guests ever reciprocated, so they just stopped hosting as well. I do think that they did it mostly out of obligation or "just the proper thing to do" and not because they particulary enjoyed it.