[ohioWfan]

Here is some information from the Heritage Foundation from 2005 to refute your hypothesis.

There's lots more out there if you need it to further correct your 'idea.'

[dakine]

Military comes from higher-income backgrounds because the opportunities out in the economy do not support the continuance of that lifestyle?
Not saying all, for a small part of the enlistees it could be a factor.
The broad brush approach to the reasons for enlisting is wrong no matter what reason is chosen.