The problem with your theory is that the individual doesn't necessarily have total control over what they do, career-wise. A person may WANT to take on those more dangerous jobs in order to earn a better retirement... however, the military may say "sorry, you're not what we need" or "We need you elsewhere" or "You're being non-vol'd to XX position which doesn't earn near as much retirement pay as your current duties do".
In the corporate world an individual has the opportunity to advance into other areas if they're not content with the deal they are getting. They can go back to school and get an advanced degree to move up in the company, move to a different company entirely, start their own company, choose a whole other career choice, etc. But with the military, while you affect your career and can help your chances, you are also dependent on what big blue decides for you.