[HeatDeath]

Just because unarmed combat is ridiculously difficult to learn to do at an expert level doesn't necessarily make it remotely useful against even the most basic technological weapons. Thats why martial arts expertise is a somewhat esoteric hobby but firearms are a billion dollar a year industry. They aren't balanced, even remotely, and there's no realistic reason to expect them to be.

Just like in real life, not every piece of knowledge or skill that you spend time and effort (XP, basically) to acquire will improve your combat effectiveness to the same degree. Unarmed combat stops being cost-effective somewhere around the level where you can trivially equip a squad with pointed sticks, let alone anything fancier.