Peters eyes were opened when Cornelius got saved! to finally see the truth. Remember that Paul had to rebuke him in Galatia because he sinned badly and withdrew his fellowship from the gentiles in Galatia!
If you don't agree that this visit from Peter to the Gentile was a one-off event, lets use scripture to decide, look at Acts 11, after Peter had to explain his visit to the Jews
17 Forasmuch then as God gave them the like gift as he did unto us, who believed on the Lord Jesus Christ; what was I, that I could withstand God?
18 When they heard these things, they held their peace, and glorified God, saying, Then hath God also to the Gentiles granted repentance unto life.
19 Now they which were scattered abroad upon the persecution that arose about Stephen travelled as far as Phenice, and Cyprus, and Antioch,
preaching the word to none but unto the Jews only.
It does not look as if Peter's eyes were open does it? Like I said earlier, Peter and the early Jewish believers were not being disobedient. All of them understood the divine timetable in the OT, the Jews as a nation have to accept their Messiah first, before the Gentiles can be reached.
Let me just give you three examples from the OT about this timetable
Zechariah 8 explains
3 “Thus says the Lord: ‘I will return to Zion, And dwell in the midst of Jerusalem. Jerusalem shall be called the City of Truth, The Mountain of the Lord of hosts, The Holy Mountain.’
Later on, in the chapter in Zechariah 8:20-23 New Living Translation (NLT)
20 “This is what the Lord of Heaven’s Armies says: People from nations and cities around the world will travel to Jerusalem. 21 The people of one city will say to the people of another, ‘Come with us to Jerusalem to ask the Lord to bless us. Let’s worship the Lord of Heaven’s Armies. I’m determined to go.’ 22 Many peoples and powerful nations will come to Jerusalem to seek the Lord of Heaven’s Armies and to ask for his blessing. 23 “This is what the Lord of Heaven’s Armies says: In those days ten men from different nations and languages of the world will clutch at the sleeve of one Jew. And they will say, ‘Please let us walk with you, for we have heard that God is with you.’”
A similar prophecy was given in Micah Chapter 4 (NLT)
In the last days, the mountain of the Lord’s house will be the highest of all—the most important place on earth. It will be raised above the other hills, and people from all over the world will stream there to worship.
2 People from many nations will come and say, “Come, let us go up to the mountain of the Lord, to the house of Jacob’s God. There he will teach us his ways, and we will walk in his paths.” For the Lord’s teaching will go out from Zion; his word will go out from Jerusalem.
Finally, the same prophecy was given in the book of Isaiah chapter 2:2
In the last days, the mountain of the Lord’s house will be the highest of all—the most important place on earth. It will be raised above the other hills, and people from all over the world will stream there to worship.
So, based on these 3 accounts, the timeline was supposed to be Jews are to be saved first, once they accept Jesus has the Messiah, then the Kingdom will be established in Jerusalem and the Jews will then be priests spreading that blessings to all the Gentiles.