I can't measure how much apathy is involved but in their defence a lack of resources and time plays a big part. A couple of years ago EH inspected scheduled monuments once a year but their resources have shrunk since then and are about to shrink alarmingly lower. Climbing up into the wilds to check on a non-scheduled feature just isn't time or cost effective from their perspective. Let's face it, the Govt. has decided, without quite saying so, that heritage protection is a luxury that they're not prepared to support.