Originally Posted by MS Fowler

You raise an interesting question.
If the real difference between Titanic effects and Pyramids is simply "time", I'd have to ask, "Why"?
What is the difference between a grave robber and an archeologist? Both do what they do for financial gain--one uses the cloak of "research" as a cover, but the archeologist still makes his living by robbing graves. What makes one acceptable, and the other detested?