Pretty much. The lawful flow of antiquities almost entirely ceased when the UNESCO 1970 Convention came into effect in 1972. Even stuff that was lawfully excava

Pretty much. The lawful flow of antiquities almost entirely ceased when the UNESCO 1970 Convention came into effect in 1972. Even stuff that was lawfully excavated and exported prior to then often has sketchy documentation showing provenance or no documentation at all. Thus, the standards for provenance documentation are low and easily taken advantage of by people peddling looted antiquities with fabricated documentation. Yes, sometimes institutions will deaccession antiquities with impeccable provenance going back to when it was taken from the ground, verifiable through catalogs and other records held by third parties. That's not most of the market.