You are probably right that there are certain jobs that are in a non deployment status. I was in one myself for my 18 month tour on the drill field and DI school that preceded it. However, all of those type of jobs to my knowledge are temporary in nature. No more than 3 years. I could be wrong. Even if there are categories like that where people are in non deployable jobs for years at a time, that is a very small number of Marines.
I did know a guy that spent about half of his 22 year career in the recruiting field because he was so good at it. But again, that’s not too many. Incidentally, that guy was stacked with more ribbons than myself who has been in combat three times and done too many deployments to count.
AAHH! The highly decorated desk commander!