The vast majority of people in modern militaries will never see combat. They are all somewhere relatively safe and merely supporting that small minority of troops who will see combat. Consequently, it is no surprise that pay is fairly low.
But in the private security world – people guarding Western and Chinese interests in unstable developing countries – those people are likely to get involved in some shooting, and so their salaries and benefits for loved ones are very high.
Still, agreed, private military is nearer 1:1.