I disagree with your conclusion. The Christian office of presbyteros is still called presbyteros in Greek, and is called priest (or occasionally presbyter) in English. My parish priest (by the grace of God and our metropolitan, he also happens to be the senior priest of our Archdiocese) was a presbyteros (or priest) of the Church of Greece for eight years. Whether you speak English and say 'priest', Greek and say 'presbyteros', or Arabic and say 'khoury' is quite inconsequential, the office is the same, and is the one to which the Holy Apostle referred in his instructions to Titus.
Nor is it clear that you can interchange 'presbyteros' and 'episcopos', though certainly in the early Church it was normative for the bishop (again an English translation of the Greek, in this case 'episcopos', derived from the Greek word) to hold the presidency of the Eucharist, now most commonly exercised by priests by delegation of authority, so the offices may have been identical initially until the Church spread beyond its initial urban setting.
"Nor is it clear that you can interchange 'presbyteros' and 'episcopos',"
Paul does when he addresses the leaders of the church at Ephesus. In fact there are more than one presbuterous, episcopous in the church, not just one.
See Acts.20:17, "And from Miletus he sent to Ephesus, and called the elders (presbuterous) of the church."
Acts 20:28, "Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers (episcopous), to feed the church of God, which he hath purchased with his own blood."