Yes, the prophets did foresee (e.g. Is. 49:6, Ps. 72:11) a day when other nations would be given light and would come to adore the God of the Hebrews, the one true God. But this is never presented in egalitarian terms. Rather, as St. Paul says in Romans 11, we Gentiles have been grafted in to God's chosen people, as a wild olive branch is grafted onto a cultivated vine.
When the magi saw the star and came to adore the Christ child, this was the first fulfillment of the aforementioned OT prophecies. The magi were the first Gentiles to recognize and worship the Jewish Messiah, and from that point on the floodgates were opened. Soon, with the preaching of the Apostles, all nations were invited to be a part of God's holy people. This wasn't an egalitarian dumbing-down, but a call to come and be part of God's chosen race. As Pope Pius XI pointed out, we Christians are all spiritual Semites. Grafted in or not, I for one am happy just to be allowed in, to be one of God's favorites, the apple of His eye.