Why does God choose to send Jesus to Earth at the end of time, and not the Prophet Muhammad, who spread Islam?

Jesus, peace be upon him, will descend at the end of time as one of the signs of the Hour. All the People of the Book will believe in him before his death, as indicated by verses of the Quran and the continuous (mutawatir) hadiths. He will descend at the Eastern Minaret in Damascus, break the cross, kill the swine, and accept nothing but Islam. Scholars have mentioned possible reasons for his descent, including: refuting the Jews' claim that they killed him, burying him in the earth, renewing the matter of Islam and coinciding with the emergence of the Dajjal to kill him, and making the religion of Islam manifest. Jesus will descend following the Sharia of Muhammad, peace be upon him, not with a new message.