They could do something immediately to rectify the shortfall by allowing security consultants to submit themselves for security clearance rather than having to be sponsored by a list-x company.
If you stop working for aforementioned list-x company, your SC will expire unless you get another job with SC clearance requirements.
As soon as you get off the merry-go-round and your clearance expires, it's next to impossible to get back on it as agencies are always stipulating that you already *have* SC clearance (regardless of what they say about being prepared to go through the process - it takes around 12 weeks iirc).
Also, will they be vetting the students before they take this course, or just do it afterwards if they apply for a position? Coz if they fail the clearance they will just take their skills to someone a bit less choosy who will probably have deeper pockets.