Ever read the Book of Revelation? I don't think the scenario is too unlikely at all. In fact, I think it's a probability. The unlikely part has to do with survivors.
Still, speaking of survival, many of the preparations and disconnected events in the book, Luicifer's Hammer are very plausible. It was one of the main motivators for me getting interested in becoming a U.S. Army Infantry Officer and in getting myself ready to survive should things get that bad. I used many of my skills after Hurricane Andrew.
If you hop on over to the thread known as Threat Matrix, you should see a list of survival items drawn up by a freeper named appalachian dweller. This is an extremely comprehensive list. There is also on that thread a list of useful tips by me.
Sounds very interesting, do you have a link for the thread you can post?
Thats what I meant; survivors from a comet and/or large asteroid strike are remote in the extreme. Those that DO survive had best be prepared to defend themselves and their supplies from those that survive the initial disaster that did not prepare.
However, I agree in principle that one should be prepared for disaster and only the prepared (and the lucky) will survive long term.
I was a 91A medic in the US Army, and I was a Boy Scout. I have food, water, shelted, weapons and ammo, commo, etc. prepared for several different senarios: 3-day, 1 month, and indefinite future.
If the worst DOES happen, you can contact me voice at 14.15 MHz. Like minded people that have prepared will be welcome in my neighborhood.