I'm not an expert in religion, but I think Christ was the incarnation of God, not the other way around, so God incarnated in Christ.
The idea of God and a monotheistic belief was growing quite strongly and there were many, many wandering prophets around the same time. If the apostles of Jesus hadn't been so prolific, it might have been another of the prophets who became immortalized. I don't believe anyone who views the Bible from the historical critical perspective actually thinks the miracles occurred as described.
If your question is more, what if the Judeo-Christian concept of a single God had never manifested, well that boggles the mind to wonder how the world would be different.