Even people who own certain gear will oftentimes opt NOT to carry it because they have never used it for awhile. For example, I have never used the whistle on my key chain for a "real" emergency. I have used a whistle for an emergency before, but not the particular whistle in my everyday carry bag. There are other such items (e.g., keychain lighter).

I imagine most people would stop carrying an item after a few months or so of non-use. When an emergency does happen, even people who are otherwise prepared may find themselves with their pants down.