“The Irishman,” the recently released Martin Scorsese film based on an allegedly true story about organized crime in and around Pennsylvania, frequently introduces a minor character along with a brief on-screen note explaining how and when they died. In almost all of those notes, the cause is violent and premature, which I presume is the main lesson Scorsese intends to impart. But the majority of those deaths are also in either 1980 or 1981, which seems random — the film is primarily set in the 1950s and 1960s, with nothing acted out between 1975 and roughly 2003.
I see general online debate over the accuracy of other aspects of the movie (and another AskHistorians post from two weeks ago with this same question but no answers), but no indication of why (or if) a large number of gangsters who were prominent in 1950s and 1960s Philadelphia would be killed in 1980 or 1981. What was going on around this time?
I offered an answer to the previous Ask Historians post here. There were also some good follow-ups about the accuracy of the movie.
Short version is that there was a burst of violence in Philadelphia organized crime in that period, but that in at least one case the filmmakers moved the date of a murder to make it fit that window.