I am trying to understand what you are saying here. Are you trying to say that no Gentiles were saved before the cross or that the Gentiles were never in focus for God to save as a whole in the Old Covenant?
Also, the Jews were clearly cut off salvation wise. That is why Paul says earlier that his desire is for Israel to be saved (Romans 10:1). This is a parallel of how believing Gentiles could be cut off salvation wise, too.
In fact, Romans 11 also warns us believing Gentiles to be not minded but to fear.
"Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:"
(Romans 11:20).
...
They were in focus, but no non-Jews were saved by Grace thru Faith prior to the Cross.
Those were not "believing Gentiles," they were the totality of the human race of non-Jews grafted in to make them available for God's Grace, heretofore granted but ultimately rejected by the Hebrew Nation. The Jews were removed, the Gentiles were plugged in as candidates for, not recipients of, God's Grace.
The Jewish Interlude is found between Romans 8:31 and Romans 12:1. It is Paul's lament for his
Brethren, the Jews. His heart cries out to and for them. You can skip this interlude, this lament, by going straight to Romans 12:1 after Romans 8:31, without missing a beat. Read Romans 8. Stop at 31. Jump right back in at 12:1. Thereafter, 9-11.
Who profits from Romans 9 through 11? Who profits from the Book of Hebrews? Answer: Everyone. WHO is the focus? Paul cries out to the Jews, while letting Christians know of his lament. Who was the audience in Hebrews? Jews. Christians can use the Book of Hebrews in witnessing to Jews about the GIFT of Grace. To whom did Paul send the Book of Romans? Who was the audience in Rome?
Remember that the Hebrew Bible, the Abrahamic Covenant, addresses a
people group. The Nation of Hebrews was chosen as a group, sustained as a group, until they wilfully rebelled, departing from our Creator's sustaining Grace. Remember that our Creator sent Moses. Remember that they turned to idols. Recall how many completed the trek through the desert ---- even after being Spiritually escorted across that turbulent sea.
Understand that our Creator came to us in the Person of Jesus for the purpose of dying for humankind while restoring to the Jews God's Grace. Remember that the leadership rejected Him. Recall that after 40 days our Lord appeared to Saul on that memorable Road to Damascus.* Understand that he, as the Apostle Paul, went first to the Jews, bringing the message of salvation by Grace through Faith, and that when they rejected him, he turned to the heathen Gentiles, the non-Jews.
Paul's ministry (Hebrews & Romans) revealed God's Amazing Grace to every creature on earth while leading the way to confessing Jesus as Savior one-by-one. How shall we witness, if we reject / neglect / ignore so great a transition?
*http://tinyurl.com/jw7k3bu