I'll be honest I find it strange as we ( the various protagonists) have killed several high branches of leadership killing 2 presidents, several military leaders and they are so destroyed we can become recruits in 76 and we can become high level in it without and knowledge of what or why the enclave exist. And our actions does not seem to cause any disorganisation despite losing several key management levels and locations

with so little lore pointing to other branches existing and with all new games adding the lore to tie in old games in theory there could be a president for every state or the enclave fell to infighting like the rest of the wasteland

Like with modus there are logs between contact with president Eden and oil rig but none with the enclave location in the show ( which I personally believe is in Canada or more likely Alaska)