Then you will say, “Branches were broken off so that I might be grafted in.” That is true. They were broken off because of their unbelief, but you stand fast through faith. So do not become proud, but fear.
Romans 11:19-20 ESV

As stated regarding v17, former Gentiles aren’t added in the place of the pruned natural branches, but their pruning still enabled our grafting in, not through creating a graft site (that’s over-extending the analogy), but by creating an opportunity for Gentiles to hear and believe the Gospel. If Paul had not been rejected by one synagogue after another, would he ever have followed his true calling of being the Apostle to the Nations?