When most people think 'Islamic extremism', they think of Al-Qaeda, ISIS or any of their spin-offs. They belong to the Sunni branch of Islam. But Islamic extremism having to do with Shia Islam is either minimized or not mentioned at all, the largest terror group having to do with that denomination is Hezbollah.
But without Wahhabism to inspire the rise of Saudi Arabia and the terrorist organizations that spawned from that country, is there a possibility that Islamic extremism could live on in Shia Islam and we could see more organizations like Hezbollah, the Houthis, who are more focused within the Middle East and only rarely strike out targets in the West? (To my knowledge, Hezbollah has only attacked one target in the Americas and that was a Jewish community centre in Buenos Aires, Argentina. They also hijacked a airliner in 1985 in Greece, but that was within the general area of the Middle East)