Star Trek is one of the few SF shows to have the distinction of running long enough to make some of their original situations outdated.
In the original Star Trek, the Eugenics wars took place between 1993-1996. Star Trek: The Next Generation was produced from 1987 until 1994, so it was being produced during that time period and Star Trek: Voyager started production after that, so those shows were actually produced during and after the time when Earth was supposedly going through a terrible war.
The Eugenics Wars were not mentioned in The Next Generation or Deep Space Nine, and were never directly mentioned in Voyager. However, The Next Generation started with Q putting humanity on trial in a courtroom modeled after trials that took place after World War III, which is in the 21st century.
In Voyage there are at least two episodes that deal with the late 1990s or early 21st century, a time that was after the Eugenics wars were supposed to happen. In Future's End, the ship Voyager is in orbit around Earth in 1996 (current time for viewers when it was produced) and crew members spend time on Earth. Everything looks as we'd expect for people living in 1996. There's no trace of the Eugenics wars or any of the aftermath. In the episode 11:59 we see Janeway's ancestor in the year 1999 and there's no trace of any recent wars.
While this was necessary, since Trek had been around so long, at that time, that it had outdated itself, it does create problems in terms of internal continuity. I realize that the Voyager producers were more concerned about not confusing newer viewers than about maintaining continuity with a show that aired 20 years before then, but there are repeated references to Kirk later in the series that do keep some continuity between the shows.
Was there ever any on-screen or canon reference to this? Was the timing of the Eugenics wars moved forward to fit a new timetable? Were they just combined with World War III, sometime in the 21st century? Were retconned dates for the Eugenics wars ever given to go with a revised timeline?
If this was never addressed in canon, did any of the novels or games provide any explanation for the discontinuity between the 1990s as the time for the Eugenics Wars and the fact that we're still here, without such wars, in the 21st century?
Please understand: I know what the Eugenics Wars were and about them. What I'm focusing on, with this question, is what was done within the studio or the writer's meetings to handle the retconning when our world caught up to the time of the Eugenics Wars and Voyager was airing episodes of their characters visiting our non-wartorn planet instead of one decimated by those wars. Or did the writers in Voyager even realize that was an issue?