Can you though (put them back in their original context :-) Isn't a point eventually reached when the original context is no longer known (let alone valid) and a new one (or nothing at all) takes its place? Avebury, Stonehenge or Whitby Abbey are now vessels for the modern, or relatively modern, imagination. The modern context of those places has now given us something else - the paintings of Constable and Turner, the writings of Bram Stoker etc.

In a word, things move on. Old barns are turned into fancy pubs and restaurants, churches into all kinds of things, other places into whatever. And though we might be able to preserve the structural remains of those places (for a while longer at least) the original context that created them has long since gone (in many cases we hardly know what it was anyway).

Perhaps those who would claim Stonehenge as part of their 'religious' inheritance would do better to say, "We don't really know what it was used for and if we did we might not like it very much anyway so we're off to build something that suits us better." Getting to that point might actually be a lot more honest in establishing a new context and one more relevant to the modern mindset :-)

Of course, hog roasts, beer/mead swilling etc will never go out of fashion so we can sleep easy in the knowledge that that particular tradition will survive (though the context in which it takes place might always be up for a bit of change :-)