In the Middle Ages, blunt force weapons such as maces and warhammers became popular thanks to the noble class, the usually bought full metal armor what made cutting and stabbing (swords and pikes) virtually USELESS. What does this have to do with dinosaurs? Lets compare T. rex with Smilodon:
-T. rex was like a warhammer/mace wileding knight: it was robust in build, resistant and relied more on force to attack. Like this it would be able to take down most heavy armored foes (on T. rex's case: large ceratopsians and hadrosaurs, even if these had a thick hide. On the Knight's case: other kinights). The down side is that it would take quite some time to kill the foe, even if he was not so heavily armored.
- Smilodon was like a sword-pike wielding knight: it was robust in build, resistant and relied to piercing and stabbing to attack. Like this it would be able to take down larger tagets more easily, but ONLY if these were not heavily armored or had great gaps on the armor (just like a swor