Replacement theology simply holds a wrong view of Israel.
The true Jew has always been the household of faith. Oh, it was a small house prior to Jesus, the Seed, arriving…only a few found it (Mat 7). Now many come from the North, South, East and West and sit down with Abraham, Isaac and Jacob in the household of faith (Mat 8 ).
Placement theology – if any man be in Christ, He is a new creature, a true Jew, the true circumcision who worship God in Spirit and place no confidence in the flesh (Rom. 2:28; Phl. 3:1-9).
Sarah didn’t replace Hagar. Hagar was never the plan. It was always Sarah. Kicking Hagar out of the house changed nothing of the promise, the plan and the purpose of God.
The Jerusalem from above didn’t replace the old Jerusalem (Gal 4:25,26). The Jerusalem that now is was never the plan. It is spiritually called Sodom and Egypt (Rev 11:8). It was simply a shadow and not the very form of the good things that were to come (Heb. 10:1).
No one has been replaced. It has always and only been the household of faith.