One thing is 'with certainty'... the Muslim Nations have never deviated from their mutual desire of seeing the Caliphate arise.....which will, despite their differences, unite them eventually against what they see as a common enemy to Islam.
I don’t know. The war between sunnis and shia has been ongoing ever since Mohammad died, that’s some 1400 years. During that time they never united as such even among a common enemy. But, in more modern times, I do believe if the west stopped supporting Islam, for whatever reasons, we wouldn’t increasingly face a dire Islamic threat on a global level, which this is.