The ecclesiastical word "church" surely has been misleading in eschatology. It is NOT a biblical word, but a man-made word read into the Scriptures and it causes mayhem. If you do a search in the Young's Literal Translation, or Jay P. Green's literal translation of the Bible you will not find the word "church". It is usually "assembly" or "assembly of God", or some such, in both the OT and the NT.

"And the chiefs of all the people, of all the tribes of Israel, station themselves in the assembly of the people of God, four hundred thousand footmen drawing sword." (Judg 20:2, YLT)

"On that day there was read in the book of Moses, in the ears of the people, and it hath been found written in it that an Ammonite and Moabite doth not come into the assembly of God--unto the age," (Neh 13:1, YLT)

'Take heed, therefore, to yourselves, and to all the flock, among which the Holy Spirit made you overseers, to feed the assembly of God that He acquired through His own blood, (Acts 20:28, YLT)

"to the assembly of God that is in Corinth, to those sanctified in Christ Jesus, called saints, with all those calling upon the name of our Lord Jesus Christ in every place--both theirs and ours:" (1Cor 1:2, YLT)

Therefore we have the OT people(assembly) of God and they are continued as the NT people(assembly) of God. The OT people of God are called "Israel" and then the NT people of God continue as "Israel". The Old Covenant believers, Israel, are continued as God's people, New Covenant believers, Israel. There is NO "replacement" here, but a continuation of God's people (the assembly).

"For he is not a real Jew who is one outwardly, nor is true circumcision something external and physical. He is a Jew who is one inwardly, and real circumcision is a matter of the heart, spiritual and not literal. His praise is not from men but from God." (Rom 2:28-29 RSV)

"But it is not as though the word of God had failed. For not all who are descended from Israel belong to Israel, and not all are children of Abraham because they are his descendants; but "Through Isaac shall your descendants be named." (Rom 9:6-7 RSV)

"For neither circumcision counts for anything, nor uncircumcision, but a new creation. Peace and mercy be upon all who walk by this rule, upon the Israel of God." (Gal 6:15-16 RSV)

"Circumcision is nothing; uncircumcision is nothing; the only thing that counts is new creation! All who take this principle for their guide, peace and mercy be upon them, the Israel of God!" (Gal 6:15-16, REB)

"Yet God forbid that I should boast about anything or anybody except the cross of our Lord Jesus Christ, which means that the world is a dead thing to me and I am a dead man to the world. But in Christ it is not circumcision or uncircumcision that counts but the power of new birth. To all who live by this principle, to the true Israel of God, may there be peace and mercy!" (Gal 6:14-16 Phillips)

Try reading this passage in Romans 11 like this:

"But if some of the branches(Physical Jews) were broken off, and you, a wild olive shoot(Elect Gentiles), were grafted in their place to share the rich root(Jesus Christ) of the olive tree(God's people), do not boast over the branches. If you do boast, remember that it is not you that support the root(Christ), but the root(Christ) that supports you. You will say, “Branches(Physical Jews) were broken off so that I might be grafted in.” That is true. They were broken off because of their unbelief, but you stand only through faith. So do not become proud, but stand in awe. For if God did not spare the natural branches(physical Jews), perhaps he will not spare you. Note then the kindness and the severity of God: severity toward those who have fallen, but God’s kindness toward you, provided you continue in his kindness; otherwise you also will be cut off. And even those of Israel(Physical Jews), if they do not persist in unbelief, will be grafted in, for God has the power to graft them in again. For if you have been cut from what is by nature a wild olive tree(Gentiles) and grafted, contrary to nature, into a cultivated olive tree(God's people), how much more will these natural branches(Elect Jews) be grafted back into their own olive tree(God's people). So that you may not claim to be wiser than you are, brothers and sisters, I want you to understand this mystery: a hardening has come upon part of Israel(Physical Jews), until the full number of the Gentiles has come in. And so all Israel(elect Jews & elect Gentiles) will be saved; as it is written, “Out of Zion will come the Deliverer; he will banish ungodliness from Jacob.” “And this is my covenant with them, when I take away their sins.” (Rom 11:17-27, NRSV)

I am not dogmatic on eschatological theories, but this is what satisfies my mind and comes the closest to how I understand this complex matter. I post it for consideration and to provoke thought.