Before the advent of Deen-a-Islam, there were certain religions being practiced blindly by a number of people in the world.
Prophet Mohammad (S) brought Islam Deen a complete code of life as how to spend life journey collectively and turn the world into paradise by spreading Peace all over the world by extending the Love, Respect and taking Care of everyone disregard of some one's faith.
Now just imagine if offering five-time prayers repeating same words and fasting for good one month stands anywhere. The results look to me all Zeros.
The video of Dr. Asar ul Islam Syed in Urdu is very convincing to me. After the death of Prophet (S), Islam spread rapidly in East and West.