A strange thing. I've never come across those survivalists types that built bunkers in the yards. I've gotten a good bit of equipment from a few of those shelters I've run across, but the occupants were nowhere to be seen. Of course, the testimony of just one person, who usually avoids overly-civilized areas at that - isn't the best rhetorical evidence. On the other hand, I've been in a lot of places, so you would think it should have occurred by now.
I'm guessing its a matter of timing. Its one thing to plan for a flood, or to escape an earthquake zone. However, that is still a localized event. The Event was global. Not much happened in the initial hours - if you weren't dependent on electric life support or in an airplane, you probably survived, and didn't even know what was going on due to the communications disruptions.
After that is when things got horrid, when people panicked, when the orbital bombardments came, and the reanimates rose. Still, you could be out in the middle of nowhere and avoid that for the most part.
Its really problematic when the utilities were gone, there was no government to direct you to get some, and no army to deal with roving looters and creatures that things just plain ended.
So, it would seem there was plenty of time to get to your shelter. There was also plenty of time to realize it was probably futile. What is the point of just you and six friends hiding from the end of the world? It takes a community to get the machine started. It takes some form of government to marshal effort to restoring society. Those who can just say "screw this - off to the shelter" really aren't the people you want for the rebuilding period anyway.