According to non-Trinitarians, why did God allow trinitarianism to become the mainstream understanding of His nature?

According to non-Trinitarians, if God's nature is *not* adequately portrayed by trinitarian theology, then why did God allow such an erroneous understanding of His nature to become so widespread among the members of the Church, the Bride of His Son? If God has the power and the prerogative to intervene in historical events, then why hasn't God made use of His divine privileges to ensure that the correct doctrine about His nature achieves widespread acceptance?