Here's an idea that doesn't break canon too badly

[raketenjagdpanzer]

One of the more spurious canonical notions is that of the limited nuclear exchange that happens in T2k that leaves an "interesting" amount of the world intact, yet also depletes the number of operational nuclear weapons to the point that Bear's Den and a couple other instances in modules that have nukes notes them as being rare.

What if things like Skyguard, Star Wars and Soviet ABM systems were in place, and while it was a case of "2400 warheads over the pole", only a (relatively) small number of them made it through such systems?

Just throwing that out there for discussion.

It'd make more sense than SIOP not kicking in and a real Apocalypse happening...