Why does Jesus wait to come back?

Because it is not yet time for His Second Coming. The final prophecies must happen first, and then His Second Coming will happen in the clouds. Jesus will not come back to earth as He did the first time. Everyone on earth will witness His Second Coming in the clouds with great power and glory. (Mark 13:26). First there has to be a great war, then the Antichrist has to come to make a false peace. Then the Antichrist will rebuild the Temple in Jerusalem and procliam himself as the Christ, for the first three-and-a-half years of his reign. Then for the next three-and-a-half years, he will reveal his true self and wage war against all those who did not accept his mark. Then the Second Coming of Christ will happen in the clouds and Christ will destroy the beast and all those who received his mark on their right hand or forehead. Jesus' Second Coming will not happen until these final biblical prophecies have been fulfilled.