“(which you must think was some infallible information transmitted by word of mouth from the bishop of Rome or something??).”
Not sure what ebb is trying to say, but I would point out that individual bishops were supposed to go around and ensure that the correct teachings were being taught and no deviations.
the individual patriarchs of each area - Rome, Jerusalem, Antioch and Alexandria (then Constantinople) also kept their individual bishops in line.
I do not understand how this relates to the Bible being the only source of doctrine. How did they know what the correct teachings were? Obviously they knew about some things, like the resurrection, by word of mouth. There were witnesses of that. Did they know things for which there were no witnesses?