Did Jesus tell the disciples the Kingdom would be postponed for nearly two thousand years?
No, Jesus did not tell the disciples the Kingdom would be postponed for nearly two thousand years. He left them with the understanding that the Kingdom was still at hand. Peter, therefore, saw the need to fill the twelfth apostolic slot in readiness for Christ's return to set up His Kingdom.
Les explains that Peter understood Jesus had left the disciples with the idea that the Kingdom was still at hand; Jesus had not told them it would be postponed for 1900 and some years. Because the Kingdom will be ruled by Christ with the twelve tribes of Israel, twelve apostles are needed. With only eleven remaining after Judas, Peter saw the urgent need to fill the twelfth slot so they would be ready for Christ's return when He sets up His Kingdom. This follows the earlier observation of 120 men in Jerusalem after three years of Christ's ministry.