In Romans I believe that Paul makes the argument that God does communicate with the entire world and the world will be judged on how it responds. The message is all around and within us, it is just a matter of listening.
The old testament prophets had a message just for their nation. Someone like Jeremiah heard from God and lit a fire demanding social reform to care for the neglected in their society. By not championing the cause of the poor the people turned their back on God.
Jesus message contains elements of the same. It also includes peacemaking, forgiveness, and love.
Maybe god speaks through prophets like Ghandi, Mother Theresa, and John Lennon. "All You Need Is Love," was a hit single and still played on the radio today. Hell, my daughter was introduced to it on a video game.