So In 2021 -- Nuclear Annhilation Isn't a Worry Anymore?

Good point, I can only think of a couple of later (but not exactly recent either) films more or less obliquely dealing with the threat of nuclear extinction: 'The Miracle Mile' (Steve De Jarnatt, 1988), 'Matinee' (Joe Dante, 1993) and 'Watchmen' (Zack Snyder, 2009).

I think maybe one reason why we don't see these kinds of films anymore since their timid resurgence in the 80's, is because everyday life has become somewhat more complicated than it used to be for regular folks, and that concerns even as important as existential threats such as nuclear annihilation have become more abstract and have taken second stage compared to the very concrete and everyday difficulties of say, navigating today's job market in a globalized economy, the difficulties of owning a house, social-media related effects on the structure of society (and mental-health consequences), deep societal divides within several Western liberal democracies, etc.

Well, I am beginning to worry about it again. There seems some likelihood of a renewed cold war with Russia and Putin has leaked info on a few nuclear terror weapons in recent years... Some sort of horrifying nuclear ramjet like our discarded Project Pluto and a drone submarine to deliver underwater nukes along coastlines -- which would yield a staggering amount of fallout plus a nice nuclear tsunami.
I suspect the current more complicated world has led people to assume that any nuclear weapons used would be one-shot terrorist or "rogue-state" affairs like North Korea taking a shot at Seattle. Of course there are still a huge number of weapons in the hands of superpowers that are not on good terms, so the reality is that nuclear war is still a possibility.
I think that contemporary films and TV tend to avoid it in part because there is the sense that it has been played out dramatically. Look at the Fallout games. They set their apocalypse in a retro '50s setting. Nuclear war is so retro...

Why are some people being unnecessarily obtuse about this question?

I was alive and well during the tail end of the Cold War. The reason why so many nuclear war movies came out when they did is that up until the early 90s, everyone had lived with this ever-present fear that nuclear war was not only imminent but was going to happen at any moment.

It didn't help much that Ronald Reagan was completely deranged in his stockpiling of nuclear weapons in the name of "MAD" (Mutually Assured Destruction) and that war hawks were pushing this idea that there could be a winnable nuclear war or were babbling "better dead than Red".

Adding to the mix is that nuclear weapons became so much more terrifying as time progressed. Whereas in the earlier phases of the Cold War, people held out the faintest hope that they could survive (like in a bomb shelter), by the 1980s, weapons were so deadly that the question wasn't whether you could survive a nuclear war or not but whether or not you'd want to.

Because of this feeling of urgency, tons of filmmakers put out a spate of films to stop what felt unstoppable at the time, as in, "OMG, we need to scare the living bejeesus out of everyone and counteract these lunatics arguing that nuclear war is inevitable or winnable or preferable to being Communist." Then the Berlin Wall fell, and the threat of full-scale nuclear war eventually faded by the mid-90s.

That's what happened. No mystery. The threat of full-scale global annihilation faded after the Berlin War fell, so there's no reason to keep making movies about it.

On top of that, I think that people have come to see stuff like The Day After and Threads as the definitive nuclear war movies, anyway. You can't really do a better job than those films did in capturing the horrors of nuclear war, and any attempt would be seen as paling in comparison.