That movie is from a time when they truly believed the only thing to worry about was radiation and fallout.
That said, it will recover. Eventually.
No it wont, we'll be lucky to be back to 19th century levels after enough people have died that what little food can be harvested is enough to support who's left. Post-WWII reconstruction was possible because we were untouched so we could ship materiel and machinery to europe and japan. Case in point germany and japan were still pretty much in ruins in the late 40's until the treat of communistm forced us to help them. Had we and the ussr been as devastated as say germany the western world wouldn't have rebuild to pre-war levels until the 70's, and only because conventional weapons just weren't as destructive, else odds are we would still be living in worse conditions than pre-war people to this day.
Then there's the lost knowledge, because the bombs just obliterate any cities, industrial and scientific installations is not like with old bombs that you could run to an air raid shelter or even a ditch and survive, you're fucked because you're at ground zero. With those people gone you're gonna be left with a ton of other people who can at best repair a car or a tractor, but not the refinery to make fuel for those.
And if Australia is going to be hit, it would be due to submarine basing (assuming we're parking SLBMs there). Even then, I'd put the chance at low.
They would still hit the cities because nuclear war is a zero-sum game and cities still have manpower that the enemy can use to mount an attack.
While there aren't any declassified maps of Australian nuclear targets we do have a partial map of Soviet targets for the mainland US.
The only places besides cities and industry are military bases, see those clusters of bombs? those are to take down our silos before they can fire. Needless to say if you're in any of those states the fallout alone will kill you.
What's the solution then, an old wine cellar?
The only solution is to not have a nuclear war. Even NORAD runs on diesel generators and once the fuel is gone they can't even pump air to keep people inside from suffocating to death.
the possibility of Cobalt Nukes
Those were never made and likely never will because contaminating an area forever its counterproductive. Consider that there are still part of France that to this day are uninhabitable due to pollution from WWI chemical weapons.
we're on the cusp of fusion power becoming viable
We're always on the cusp, its always just around the corner.
Nuclear use would most likely force NATO retaliation.
It likely wont, not against a non-NATO target, because to retaliate means nuclear suicide to avenge another country. Even W.Germany was doubtful that if hit they would be "avenged" this way since why would France, the UK and the US sacrifice themselves for them?
Failure to respond would destroy what's left of western deterrence and promote nuclear proliferation.
The fact Ukraine got invaded after giving up its 600 nuclear weapons despite a promise of full NATO intervention if that happened its enough to get many countries to reconsider the NPT. However the latter is kept alive thru a mix of economical and political coercion, there are plenty of turnkey nuclear countries out there that have been told developing a bomb would put them in the same kind of isolation N.Korea has.
