In the Nutshell: The question at the end, resorts to the will of Allah. Any rational explanation would boils down to why this but not that. It directly depends upon to the Divine Ordained Decree or Predestination.
Many things can be said. It has already been written that Muhammad PBUH will ascend as the last Prophet, who will complete the revelations and the seal of prophets is on them. So the further critique can be as for why the Prophet Muhammad, not the Jesus as the last Prophet and thus the argument goes to the fallacy of Ad Infinitum.
ۚ إِنَّ اللَّهَ يَفْعَلُ مَا يُرِيدُ - 22:14
Indeed, Allah does what He intends.
As these things aren't answerable. Everything is within divine power. Something that is like a possible entity is of course also only possible (otherwise, it would not be "like" it), not necessary or intrinsically impossible.
The answer deduced from the past scriptures are prophesying the coming of Prophet Muhammad, peace and blessing of God be upon him and the Sharia with him. So the corruption will be fixed by the reviving the same teachings with the new messenger.