That doesn't defeat my point- is the smaller/poorer army using best practices?

When all things are the same, the army with more will win.

When all things are not the same, there are little bonuses that can cause the smaller/poorer, malnourished army to win against those with machine guns. Often it's just knowing the territory. Again though, these people are individually making decisions. There isn't some massively smart borg ball sending individual orders to shoot 3 inches to the left to each drone.