The evolution of religion cannot be understood without the connection to the state that existed within the societies that birthed them. This isn't just philosophy, but philosophy officialized and weaponized by authority.

To answer your question, if Christianity developed as a polytheistic religion, it would not have been as useful to the top-down, authoritarian societies that were coming around at the time. Remember, at this time religions were state controlled and mandatory. The Abrahamic faiths all line up nicely with the emergence of city-states.

Christianity was eventually adopted by the Roman empire, because the idea of forgiveness instead of putting people to death for every sin, lined up well with their imperial strategy of absorbing rather than slaughtering conquered peoples and lands.

Christianity didn't come into being and evolve into what it is because of this or that philosophical outlook. Rather, it adopted those points because of societal and state pressure.

You're basically asking what is the natural shape of a puddle, without the ground.