Lets look at the scripture in context and then see what St Augustine thought of that
Mat 16:14 And they said, Some [say that thou art] John the Baptist: some, Elias; and others, Jeremias, or one of the prophets. Mat 16:15 He saith unto them, But whom say ye that I am?
Mat 16:16 And Simon Peter answered and said, Thou art the Christ, the Son of the living God.
Mat 16:17 And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed [it] unto thee, but my Father which is in heaven.
Mat 16:18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
From St Augustine:
...Why have I wanted to make this little introduction? In order to suggest to you that in Peter the Church is to be recognized. Christ, you see, built his Church not on a man but on Peter's confession. What is Peter's confession? 'You are the Christ, the Son of the living God.' There's the rock for you, there's the foundation, there's where the Church has been built, which the gates of the underworld cannot conquer. Sermons, Volume III/6, Sermon 229P.1, p. 327.
Furthermore, Jesus gave him the Keys to the Kingdom, (vs.19), which is a reference back to Isaiah 22 referring to the office of Prime Minister.
This essentially made Peter the first Vicar of Christ. In other words when the King gave the Keys to the Kingdom to the Prime Minister, it was meant to be for the office and to be handed on to the successors. Since then 262 Popes have succeeded Peter to this day. One more reference is helpful: at the end of the Book of John 21:17, Jesus, after asking Peter three times if he loved him, then told him to "feed my sheep".
Keys are useless unless they open something. Once it is open they are no longer needed..
The writer says that the keys were a fulfillment of Isa.
To credit what was a prophecy of the coming of Christ to peter is almost blasphmy
Isa 22:22 And the key of the house of David will I lay upon his shoulder; so he shall open, and none shall shut; and he shall shut, and none shall open.
That is speaking about Christ NOT PETER
Who is speaking in Revelations? is it Peter?
Rev 3:6 He that hath an ear, let him hear what the Spirit saith unto the churches.
Rev 3:7 ¶ And to the angel of the church in Philadelphia write;These things saith he that is holy, he that is true, he that hath the key of David, he that openeth, and no man shutteth; and shutteth, and no man openeth;
The Key that was given to Peter was the gospel that he would open to the Gentiles. That was fulfilled on Pentecost as he addressed the nations and each man heard in his own tongue.
The author just lifted talking points without reading the scriptures for himself!
Yes, it is possible to read Matthew 16 in this way, that the Petrine Office is built not on the person of Peter but rather on the confession of Peter. As Catholic I have no problem with that reading. No one suggests that the elevation of Peter was due to anything other than his faith.
Regarding the Keys, what you offer is sheer speculation. No connection with the Gospel is made in the text, -- you just made it up. The connection is with entering heaven, and with binding and loosing on earth that will, on the promise of Christ, obtain in heaven. That power is also given the Apostles in Chapter 18, where, again, it is linked with legislative power, and not with the scripture.