Serious question – not rhetorical, not flippant, frankly curious.
The ineffectiveness of God’s communication with humanity is amply attested in the Bible, and the Qur’an. This could be documented, as needed. God communicates, but people don’t respond in anything like the appropriate or desired fashion to the communication. Why not? Why doesn’t the omnipotent, omniscient, omnipresent God of the theological tradition do better than the average parent, or teacher, or advertiser?