That's an assumption on your part as the Bible says no such thing. My only evidence is the word of God.
Bishoprick means 'oversight'. For the church to be established (which was yet to happen at this time), God wanted 12 apostles in place. If your hypothesis were true, however, then we would see a replacement for James after he was killed by Herod and for every apostle that was killed.
So what was Peter doing? What is the "office" occupied by Matthias?
God wanted 12 apostles in place.
And Paul made 13.
If your hypothesis were true, however, then we would see a replacement for James after he was killed by Herod and for every apostle that was killed.
True enough, if the Acts of the Apostles were a highly detailed history book in the 21st century manner of historical documentation.
Then we could put aside all the discussion and get down to the real work, prayer.
All were replaced. We call those replacement bishops. The first bishops were relaced by other bishops and so on down to now. Some replacements were recorded. Loss of records does not mean that the act did not occur or that it was blotted from reality.The paper does not make the reality.