ok so tf what
Okay, so what? You have decided that Rome can err and that you may sit in judgment using the Scripture to comfort you with that possibility and you say, "So what?"?. Okay, my FRiend, here's what... That is precisely the kind of reasonable evaluation of Rome which brought about the Reformation. You have entered the realm of Martin Luther, John Calvin, Martin Zwingli, and a host of others who finally said...Rome has made a mistake.
In the case of the Reformers, they found hundreds of mistakes Rome made using the very document you are using...the Bible. They noticed that hundreds of years earlier, Rome wandered off the Gospel path and onto a road of self-made religion. Just as you have identified possible error with the selection of a "pope", they identified error with Rome's basis of salvation, Rome's need for priests, Rome's sacraments, Rome's purgatory, Rome's indulgences, Rome's Mary fetish. The list goes on.
If you are in a questioning mood (you already have driven outside of Rome's lines with your concern), you might as well consider further...could Rome make mistakes on other claims? We have found unequivocally, yes. The mistakes are radical and deep and important. But, the Bible (just as you have found) offers correction to those mistakes...the truth just does not lie with Rome.