There are definitely periods, sites, and cultures where we believe the majority of finds that would have existed are already lost to us from decay processes (us

There are definitely periods, sites, and cultures where we believe the majority of finds that would have existed are already lost to us from decay processes (usually modeled exponentially). An example is the category of classic mimbres black on white pottery depicting animals. This is a type of artifact that certain archaeologists would like to study and also has a high black market value. The scarcity of examples with secure provenance indicates that few remain to be found as a result of looting and relevant experts don't expect to find many more.