These threads are always tough to answer. First, none of us really know what an "end of the world as we know it" scenario is going to look like. Is it an invading military force from overseas? A repressive government trying to put down its own citizens? A complete breakdown of society due to disease, natural disaster, etc.?
Second, where do you live? I live out west on 35 acres surrounded by ranch land. Pretty sparse population and sight lines that can extend out 500+ yards. If you live in urban Detroit your set up probably needs to be different.
Third, your own capabilities. Are you a 25 year old guy with 20/10 vision who does CrossFit 5x a week and shoots 1000 rounds a week? A 67 year old guy with mediocre eyesight, an astigmatism, and a bad back (me) who's happy if he can get to the range once a week? An optic that works for the 25 year old might not work for me.
Fourth, personal preference/what you've trained with. Some people can't get comfortable behind an LPVO. The scope weighs too much, the eye box is too tight. They don't like repeatedly transitioning between 1x and 8x. If they've got excellent vision and in the urban environment where they live the likelihood of a shot beyond 200 is remote a red dot (maybe with a magnifier) could be the ideal set up. If light weight, simplicity, durability, an etched reticle and some magnification are all something you want, maybe a prism is best for you. You get the idea.
Ultimately, I suppose these threads have some utility since they can acquaint you with what's out there, the strengths and weaknesses of a number of different set ups and what others preferences/solutions are. But ultimately you need to figure out what works best for you given your preferences, your abilities, your environment, what you've been training with, etc.
