Maybe all the smart ones and rich enough ones have fled the country and all that is left are the slackers and useless idiots who don't or can't flee. Would you want to be 25 years old and walking down the street minding your own business when a press gang snatches you off the street and drags you kicking and screaming into the military? Plus, I'd imagine they emptied out their prisons and jails of convicts with promises of freedom whenever the war ends. Gotta keep recruiting fodder for the front lines.