First off: What makes P&S, imho, infinitely kinder than the Doomsday '83 deal where everyone wakes up to realize they have 20 minutes to live (AP teletype
*shudder*) is the prep time. As the clock approaches midnight, you can imagine major hollywood studios and record labels taking all sorts of byzantine measures to protect their most valuable physical assets - old mines, caves, offshore oil rigs, islands, really really neutral nations with no US/USSR bases for hundreds of miles, ETC. CEOs would be screaming at their subordinates that they don't want to be the one company that was dumb enough to leave everything in a city incinerated during a "limited" exchange.
Now whether anyone can FIND these stashes after the fact is a different story. Magnetic tape has a shelf life of several decades give or take, assuming ideal environmental conditions. Some would be recovered, some would be stumbled upon later like the Terracotta Army, and some would rot away in their safe hiding place.
Other random thoughts:
My grandmom used to tell us about how singing at home around a piano or ukulele was one of the dominant forms of entertainment for her parents generation. So it would be again. Folk music would rule the Earth.
Would the British Government really not make *THE BEATLES* master tapes part of METHODICAL? If so, shame on them because those things are arguably the UK's greatest cultural treasure, full stop.
Rap music dies in the womb. Sugar Hill Gang, Planet Rock. That's
it. No Run-DMC, no Rakim. It would remain the faddish novelty that cynical music critics claimed it would be. T_T
The Roland TR-909 never gets released, but there should be plenty of TR-808s laying around in Australia!

(okay, maybe Trap music will survive lol)
Speaking of which, Electronic Music stops dead in its tracks for....a decade? Eventually I could see someone brilliantly jerry-rigging up some small, cheap, versatile drum machine/sound module that becomes ubiquitous and indeed the backbone of several genres.
Given the demographics of urban areas, African-Americans are going to be rarer than elves after the fallout settles lol. RHYTHM BECOMES EXTINCT!

(lol couldn't resist)
The thing being, how well would anything of editing and film production survive?
We could end up essentially with "Be Kind, Rewind"
IMHO this does human creativity a disservice. There have been
many great films done on a shoestring budget.
Such as Mad Max.
