We don't really acknowledge in history class just how lucky the west got with Temüjin dying and stopping the expansion that was literally right at our door.
Edit: The sibling comment is grossly misleading, the west barely won against a scouting battalion that we had time to prepare for that was frozen and starving because the greatest wingman in history tricked the army into taking the long dangerous way through the mountains and sent us a heads-up.
The Mongol army wasn't primitive, it's that their purposeful strategy (and what made them so dangerous so far from home) required they plunder food and supplies regularly along the way. It made it so they didn't need huge supply lines and could outmaneuver armies that did.
