Because the Armed Forces offer shit pay and benefits unless you're an officer. No one joins as an OR-1 unless they're one of the few natural born fighters, a so-called Patriot, or obsessive about 1 particular part of the military.

My brother only joined because his only goal in life was to fly helicopters for the RAF. If he had been happy simply being a pilot he would have a much higher-paying role in the private sector.

Furthermore, I actually want to join the Armed Forces in a logistical or organisational role, but I am unable to do so due to health restrictions (Lung, leg, knee, back, eyesights problems). Because of this my talents with logistics and organisation will never be utilised by the armed forces, no-matter how much I want them to be or how useful they may prove.