Okey Assume Islam is destroyed completely . Will all problems humanity face will end??? As long as Lust ,anger ,ego and passion towards wordliness exists in this world problems exiss in this world. It is because of past deeds(good and bad) people are born in this world. As long as Prarabdha(good and bad) exists people will fall in to the trap of Maya(Lust ,anger ,ego and passion towards wordliness)
So all chant the Holy name of Lord Narayana and attain moksha from the cycle of births and rebirths...