Legion, you can have fancy technology, but that doesn't over power the will of a true warrior, the Legion's men are trained from a very young age to kill.
So are the Enclave, even the civilians are trained in basic combat and often walk around the ENCLAVE with Laser Pistols (good ones!), Rippers and Plasma Grenades; that's how militarian the Enclave society is. They are all fanatically devoted to a single cause, even the civilians, and back up their devotion with constant physical exercise and combat simulations like OP: A.
You can have "the spirit of a warrior", but if you swing a machette at a suit of Advanced Power Armour then it would probably break. Not to mention the sheer gulf in terms of even basic logistical equipment (eg handheld radios), transportation (vertibirds) and
actual medical equipment, a [censored] Auto-Doc isn't a
luxury in the Enclave.