If we could change the past, there's a lot of things we could do differently in the Middle East to prevent the rise of Islamic terrorism. However, we can't roll back the clock. ISIS, Al Qaeda, and other terrorist groups are well established and there're not going to disappear nor are they going to abandon their goal of a worldwide Jihad just because we ignore them. The time for that has long past.
No one suggested changing the past, only that we learn from it and not repeat all the mistakes that led us into the imbroglio that we currently find ourselves in.
Bye the bye it's not reasonable to suggest the goal is "worldwide Jihad", the stated goal of the Sunni Radicals is and has been control of the bulk of the Arabic world and the elimination of the Shia apostates, thus the attempted resurrection of the Caliphate and the antipathy toward the Persian Shiites.
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To fight and conquer in all your battles is not supreme excellence; supreme excellence consists in breaking the enemy’s resistance without fighting." -- Sun Tzu, the Art of War