There's a common misconception that the US volunteer military is only poor people.
Surprisingly enough, the top US income quartile enlists at a higher rate than the bottom income quartile. There's a big list of things that disqualify recruits, not having basic literacy, no recent prison time, no high school dropouts, obesity standards, mental health standards, no marijuanas use, no children...
Afaik, in times of ancient Rome men who gave orders to fight were standing in front of the people they gave orders to, not in some remote office or bunker.
As for wall Street and conscription - they would find a way to get their sons out of this trouble I am sure.
In ancient Rome everyone in the elite had to serve a few years as an officer in a legion.