What if that perfection went on in OT times and Jesus broke the circle and the reincarnation cycle ended?
Jesus does mess up the classical concept of reincarnation because he forgives sin.
Therefore, the cycle of karma is broken.
But even in the OT there was provision for forgiveness of sin for the Hebrews.
Also one sows and another reaps so that they can have joy together--another blow to karma.
Another problem with reincarnation for Christians--you are subject to forces that are dependent on your own behavior--if you are bad you come back as an animal, if you are good you come back as an enlightened guru. Who needs Christ? It's another 'I can do it myself' religion. Furthermore, it is socially deterministic. All those poor people living on the streets of India were put there because of their own behavior in another life, caste, whatever--so there is no reason to help them--nor are they able or allowed to better themselves in society. They are stuck until the next life.
God is either very detached and remote in these religions [budhism] or very demonic.
I wouldn't trade Christ for any of that.
36And he that reapeth receiveth wages, and gathereth fruit unto life eternal: that both he that soweth and he that reapeth may rejoice together.
37And herein is that saying true, One soweth, and another reapeth.
--John 4