JW's repeat MT. 24:14 like a mantra.
But who was he speaking to, us Gentiles in the Church age? No, he was speaking to the Jews, God's covenant people. Mt. 24:14 applies to literal Jews during the Great Tribulation, AFTER the church age has ended.
Keep in mind that the OT prophets did not see the Church age. The 69th of the 70 weeks of Daniel's prophecy culminated with the appearance and sacrifice of Jesus Christ. God still owes the Jews one week, the 70th week, the Great Tribulation week. That's when the "Kingdom" message will really matter.
So, what was the message that us Gentile believers were supposed to be preaching? Did Jesus have a special message for us to deliver? He certainly did. Jesus died at the behest of the Jewish religious leaders he was sent to save. But, he didn't stay dead!
The resurrected Jesus Christ then turned his attention to the fledgling church and gave this command for us in Acts 10:
So Peter opened his mouth and said: ..... He went about doing good and healing all who were oppressed by the devil, for God was with him....They put him to death by hanging him on a tree, 40 but God raised him on the third day and made him to appear, 41 not to all the people but to us who had been chosen by God as witnesses, who ate and drank with him after he rose from the dead. 42 And he commanded us to preach to the people and to testify that he is the one appointed by God to be judge of the living and the dead.
Q. Why aren't Jehovah's Witnesses declaring the good news that Jesus himself will judge the living and the dead?