Why Didn't God Preserve Other Scriptures?
I think that this question might be better answered by someone who believes that the previous scriptures were significantly altered. It’s true that previous scriptures are not available in their original form and there are errors in translations as well as interpretations. However, there are are errors in translation and interpretation of the Quran as well. Factions within Muslims don’t disagree in “some” beliefs; there are fundamental and ideological differences among different interpretations of Islam.