It is very possible this is no longer true.
It is very possible the true derivation of the Church rests in SSPX, other independent groups, and certain orthodox elements within the Church proper, but not including the pope.
I disagree, as your statement is not consistent with Christian unity. Additionally, there may individuals, or groups of individuals who don’t cleave to the Magisterium, (I think that will always be the case), but that doesn’t mean the Pope is leading is leading us down the primrose path