I think that the real issue is not that swords became useless. It was a world inwhich sword were an instant kill tool. They didn't even had a proper hit box, or anyway was something impossible to avoid. So basically just randomly swinging them would kill anyone without any fail. The consequence of such a broken weapon is that it doesn't require any martial training. So basically nobody needed to learn swordmanship.Soulcalibur characters are crying
edit: wait come to think of it even in Soulcalibur a slash of sword doesn't cause fatal damage huh
To be fair do you think many of the corrupt assholes of this world would pay attention to the appearance of random fighters they've killed?Wait... They killed people by the hundreds before. They just NOW figured out that people killed by swords were resurrected? That should be fairly obvious early on