I don't think so. T'Challa promised the cooperation with international community and ended the isolation of Wakanda but sharing vibranium on a massive scale was still too dangerous. Especially after T'Challa's death, the other countries sought to take vibranium by force and given the context of African colonization and the pillaging of its resources, being cautious was natural. I mean come on, France literally send troops to Mali to take vibranium by force. This cannot be justified by "promise" or whatever. Sharing the resources is a choice, not an obligation.