Odds of Hanging On
There are so many different paths as an ultrasound technician that you'll never get bored. As long as you actually like the field, there's no reason that you won't be able to find a way to make the career work for you.
If you're looking for comfort, you can find a position at a doctor's office or clinic and stay there the course of your career. If you get antsy after staying in one place for too long, you can become a supervisor or manager of the sonography department—or split the hospital scene altogether and become a university professor. Goodbye, orthopedic shoes; hello, tweed blazers with elbow patches.
If you're the really independent type, you can even work for yourself. You might work as a gun for hire with several clinics, or even be a sales rep for ultrasound machine manufacturers. Just don't try to sell them door-to-door. Can you imagine trying to drag one of those machines up the steps of somebody's porch?