Had the Jews lost sight of God's plan for the Gentiles by the time of Jesus and Acts?
Yes. By Christ's earthly ministry and on into the Book of Acts, the Jews had lost sight of God's plan for the Gentiles. They resisted the idea that God would save Gentiles, as seen with Jonah, the Canaanite woman, and the riot when Paul spoke the word Gentiles in Acts.
Les teaches that even by Christ's earthly ministry and on into the Book of Acts, the Jews had lost sight of God's plan for the Gentiles. This mindset was already present in Jonah's day: when God told Jonah to go to Nineveh, he went west instead of east, because he thought those Gentiles had nothing to do with his God. Yet God can save Gentiles when He wants to. The Jewish mindset was that God had no time for pagan dogs, and even in Christ's earthly ministry this was implied with the Canaanite woman, who asked whether the dogs could eat the crumbs from the master's table. The Jews were in the place of privilege and had the Word of God, but the Jews took that to the extreme. So when Paul came back after his missionary journeys among the Gentiles and told them in Acts, the minute he spoke the word Gentiles, a riot broke out. God's whole intent and purpose was that Israel, as a kingdom of priests, would at one time go and evangelize those Gentiles.