In a society with millions of people where freedom of speech and freedom of conscience exists, there will inevitably be diversity in beliefs. That is simply a logical consequence of a free society. In order to obtain the institutionalized unity that Rome requires, there would have to be coercion and intimidation involved. Otherwise, it is not humanly possible to get.
There is no denying that Jesus Christ desires unity in the church. He despises factions amongst His people, as such is an indicator of carnality. Truth is of utmost importance. It ought to be sought after at all costs. But we are imperfect beings. Divisions have existed in the church since the time Paul wrote his first epistle to the Corinthians.
Ironically, Paul never mentioned the Magisterium of the Roman Catholic Church as being the means of preserving ecclesiastical unity in passages relating to that very topic (Ephesians 4:4-7; Philippians 4:2-3). Jesus Christ does not refer to a Papacy in His prayer to God for unity amongst brethren (John 17). That should make one doubt whether the papal office existed in the first century.