This is circular reasoning. Who caused them eventually to be worth millions? Are the present inhabitants of the source of these "treasures" willing to pay what they are "worth" today? I didn't think so.
A treasure, as anything else, is worth no more and no less than what someone is willing to pay for them.
Let's suppose. Suppose all these treasures are returned no questions asked. Not even the expense made to restore and preserve them, or to warehouse them in special environments.
Further suppose that the present inhabitants of these sterling countries decide to sell them to the highest bidders. Would you prevent them from repeating the original mistake? By what authority?
And if not, what's to prevent the repetition of this charade in another 100 years?
I believe you and I are saying the same thing. I believe all antiquities should stay right where they are at present, including the British Museum. In this particular case, if Peru can prove that these items were "loaned" then Yale should give them up, if not......to bad for Peru. It will be interesting to see how a court of law rules on this. My guess is universities and museums will be forced to return these objects in the future.....globalism and all that....