Odds of Hanging On
Once you go archivist, you never go...not archivist. Basically, once you're in that position (especially with a master's or PhD), and you keep to the Code, you're likely to stay there until you quit/retire/die of paper cuts. As with any job, you'll be at the mercy of funding. If you work for a corporation or movie studio, you'll probably be fine as long as the company stays in business. If you work in a publically-funded museum or university, you'll have a job as long as there is money budgeted for that job.
Fear not, future archivists―everyone wants things organized, but most people don't have the patience for it. They're much more willing to throw cash at you and let you deal with the mess.