Utopia

Once the world came very close to professing one common monothestic faith under the banner of Islam. However there was a secretarian split during Islam's long history, that gave rise to splinter religions like Judaism and Christianity.

It is silly of me to speculate a world with one common religion but I cannot help thinking that things could have been different. Israel would co-exist with its Arab neighbors and America would not give its blind support to Israel in spite of all the mischief Israel is doing much to the annoyance of the Arabs.
There would be no 9/11, no War on Terror and no Islamiphobia. We can conclude that the troubles in the world today is secretarian based.

There is no way these two run-away religions would ever come back to the fold. God says in the Quran that He had placed a veil over the hearts of the unbelievers. So be it.