Because while things may have been well designed originally or planned including all the fancy redundancy, after years of no major issues it becomes a target of its own success: cutbacks and people saying "see, we never needed it, and look at how much money we can save". Such is the way of things.
If you personally are worried about 911 services being out then go write down the various 7 (or 10-digit if your exchange requires it) numbers for your local emergency services. 911 is not an exclusive to reach them, just the easiest. Whatever happened to the days of the list of those various numbers on the fridge? I'm not even that old and I remember my parents having the list posted just in case.