I’ve heard estimates the “extremists” are 15%. That’s 330 million extremists, or imagine the entire population of the United States. The non-extremists are like lemmings. They will not challenge the extremists and they will agree with them rather than be killed. So, for intents there are 1.5 billion extremists or extremist enablers. Oh, boy.
Thorough history motivated minorities make history because they are willing to go the distance to dominate and intimidate the indifferent masses. Most famous is the case of Lenin's Bolsheviks who numbered around 25, 000 when they staged the October coup and seized the Russian government. Their determination, competence, ruthlessness and zeal acted as a magnet attracting hundreds of thousands of others and terrorizing the masses. Against such a scenario the only and today impossible) scenario that would lead to the defeat for the time being of Islamism would be a war of near extermination such as the US waged on Japan from 1942 to 45. Only if several large nuclear weapons are exploded in or on American cities would this possibly come about . A caveat, after 9-11, which was a Pearl Harbor type event, watching the way the leadership class in the US stumbled around and half assed apologized for the Muslims I think even millions of casualties might not produce a determination to lay Islam low.