Exploiting chinks in armour was a job for specialist armour-piercing weapons (warhammers, rondel daggers, etc), not fencing blades.
Neither early gunpowder weapons nor fencing swords made armour obsolete; mass armour for infantry was standard up until the dawn of the Napoleonic era, and armoured cavalry lasted through that. There was a lot of heavily-armoured pike & shot stuff between the Crusades and Napoleon.
Armour didn’t really disappear until gunpowder weapons became reasonably accurate, several hundred years after their introduction.
