They already lack the range and/or TTK of other weapon types. It is just a thing about skillgap. A bot with trash movement and trash positioning will lose every fight while using a handcannon, because its strength lies with peekshotting, doing significant damage without having to stay out of cover the entire time. Every sandbox has stuff better suited for better players and stuff better suited for worse players. You will still get clapped by the better ones when you force them to use sth else by making handcannons completely unusable.