Uh, there's a perfectly valid reason for us not to have joined the military. We're too rich.
Any individual who who has a net worth in excess of.... Can't recall, but people who are independently wealthy to a significant degree are refused military service usually, due to there richness making them a massive target.
Military refuses people that would specifically be targeted if they joined.
From what I understand that's not actually the issue.
The problem is that a lot of the military's punishments for low level stuff involve docked pay.
Which doesn't matter at all to someone earning millions, or in Revy's case billions, of dollars/credits a year.