TECOM has been replaced by an AI system that forces the player to hit the space bar 30 times and do an obstacle course to be granted access to the group. Not only does this do nothing for training, it broke within a week of its release. 

A large part of the attraction to the Marine Corps is its bootcamp. This is amplified even more when you are on Parris Island, a game meant for training recruits. The lack of Drill Instructors and active recruit trainings not only takes away from the quality of Marines, it takes away from the environment of the game, morale, and activity. There will never be a lack of people who want to be DI's. It is the most interactive job within the Marine Corps.

There are currently at least 15 people who are willing to drop their current billets and join TECOM if it was opened. There wouldn't be an issue opening it for amount of members. Doctrine is already made for RT, Drill Instructor School, OCS, WOCS, etc.