IPSC and USPSA are not the same organization. They have different rules. Today there are over 100 active IPSC regions - https://www.ipsc.org/ipsc/regions.php
As of today USPSA is one of the regions of IPSC. If USPSA rules are drastically different, the question is when does IPSC kick out USPSA to be their own sport and a new IPSC region is formed in the US?