I liked Alea's concise, "hammer people with portable skills into submission" line.
In the military, no matter what your skills are (or their portability), you must follow rules and orders, even if they are wrong, illegal or unreasonable. Not the case in civilian-run companies.
His follow-up sentence defines the problem even better, "after a while, you are just going to find yourself managing submissive people who have nowhere else to go."
Blue