Why did falcata style weapons disappear?

[blitzkrieg80]

short thrusting and slashing gladius, which is basically superior to any other sword in the world when correctly utilized.

care to support this completely subjective, if not grandiose statement with some empirical data?

he spoke against your argument and you should not speak as if you're an expert if you're afraid to have someone speak against your argument, or you could attempt to word it in such a manner that there is no possible objective attack- which was not the case here... i agree with Phillipus. You forgot to mention that the Romans DID NOT in fact invent the weapon and DID in fact borrow the technology like many other 'superior Roman' tactics and technology. If it weren't for the need to adapt to prowess of the Italic tribes early on, Rome would still be fighting quite different and quite outdated. Without a decent reason to adapt, there is little technology innovation...