All very well securing your house, but how would you survive long term? Food, water etc: we'd be like the prey we hunted, constantly alert and looking for danger everywhere we went: I don't think that most modern civilised societies would stand the strain of living like that. People aren't used to being as wary as a fox wherever they go. The 'living' population would be down to about 1% in very little time at all, and I think that any group that did survive would have to remain fairly small or its needs would overwhelm the numbers of people very quickly.
I love post-apocalyptic fiction: