Tell that to the Greek/Eastern Orthodox Church. They lay as much claim to the direct lineage to Rome as the Catholic Church does.Hey don't argue with me.
However the Greek, Eastern Orthodox and/or Russian Orthodox (pick a name) are all 'Catholics' too. Yes there was a split (Great Schism) over the 'Bishop of Rome' being 'supreme', but reconciliation is ongoing.
At midnight Mass one of the priests serving was introduced as being Eastern Orthodox. What are the major differences?
So maybe Roman Catholics will come back to the one true church and no longer be a sect?
And the Orthodox were correct in emphasising that the Bishop of Rome is just the first among equals (equals being Patriarchs). But there is a need for direction and that is witnessed by the Church standing up to repeated attacks by pagans from Vikings to Slavs to Baltics and Saracens.