The scripture cited was only one example of the many, many references to the Gentiles being included in God’s salvation.
The New Testament shows this beginning to be fulfilled, even within the earthly ministry of Christ.
example- when Jesus remarked on the faith of the Roman centurion, whose servant He healed, and prophesied of many who would be like him.
“When Jesus heard it, He marvelled, and said to those who followed, “Assuredly, I say to you, I have not found such great faith, not even in Israel! And I say to you that many will come from east and west, and sit down with Abraham, Isaac, and Jacob in the kingdom of heaven.”
Matthew 8: 10-11
example - the incident when crowds of Samaritans (half Jew/ half Gentile) came to faith in Christ, recognising His universal mission.
“And many of the Samaritans of that city believed in Him because of the word of the woman who testified, “He told me all that I ever did.” So when the Samaritans had come to Him, they urged Him to stay with them; and He stayed there two days.
And many more believed because of His own word. Then they said to the woman, “Now we believe, not because of what you said, for we ourselves have heard Him and we know that this is indeed the Christ, the Saviour of the world.”
John 4: 39-42
example - the testimony of John the Baptist, identifying the universality of the mission of the Lamb.
“The next day John saw Jesus coming toward him, and said, “Behold! The Lamb of God who takes away the sin of the world!”
John 1: 29
example - while preaching His inaugural message Christ clearly alluded to His rejection by His own countrymen and identified two Gentiles who were cared for by God in the time of Elijah and Elisha, much to the anger of those who heard Him.
”Then He said, “Assuredly, I say to you, no prophet is accepted in his own country. But I tell you truly, many widows were in Israel in the days of Elijah, when the heaven was shut up three years and six months, and there was a great famine throughout all the land; but to none of them was Elijah sent except to Zarephath, in the region of Sidon, to a woman who was a widow. And many lepers were in Israel in the time of Elisha the prophet, and none of them was cleansed except Naaman the Syrian.”
So all those in the synagogue, when they heard these things, were filled with wrath, and rose up and thrust Him out of the city; and they led Him to the brow of the hill on which their city was built, that they might throw Him down over the cliff. Then passing through the midst of them, He went His way.”
Luke 4:24-30
I could list all the references to Gentiles being converted throughout the rest of the NT but space does not allow.
The mission of the Messiah was always to all people, Jew first and then Gentile, as prophecy and as testimony confirms.