History happened. We can see in history the Apostolic era, and the times immediately following that era, and what happened. Largely, what happened, was that the Gospel spread, and Christians were killed, a lot of them were bishops, along with the Apostles.
(And James the Just, the 'Brother of the Lord,' the first bishop of the church in Jerusalem, which disappeared from history when Rome forced all the Jews out of Jerusalem. Up to that point, the church in Jerusalem was administered by Jewish bishops, beginning with James, whose appointment to the office of the bishop of Jerusalem was authorized by Peter, John, and his brother James; the Apostles.)
Of course all the churches were united together. That remained, until the 'Orthodox' churches in the 'East' schismed with the 'West.' So the one Body of Christ split into two. Then, in the 'West,' the Church's temporal power was targeted in the 'Reformation,' which created 'denominations.'
If you compare 'denominations' according to adherents, there are ten times more Catholics than the next closest church, which is either the Greek or Russian Orthodox church, idk which, and then after these, is either another Orthodox church, or the Lutheran church, or perhaps the 'Church of England,' I really am not sure, but the Catholics outnumber the next nearest by at least five, or ten. It could be more than 10.
Where are the bishops? 1st Timothy 3:1 KJV. There are Catholic bishops, and there are Orthodox bishops, and both those churches are ancient. There are Anglican bishops, but the Anglican church was invented by King Henry the VII in the 1500s, so they can't descend from the unbroken chain of the imposition of hands used to consecrate all bishops, starting with the Apostles creating the first generation of Church bishops themselves, through the laying on of their own hands, like do the Catholic and Orthodox bishops.
So the bishops are Catholic and Orthodox. That's where 'the Church' from the Bible is today; wherever the bishops are. 'The Church' from the Bible was administrated by bishops, the Apostles consecrated bishops all over the world when they spread the Gospel, obeying the Lord's command to them in Matthew 28:19-20 KJV, and there are bishops today.