20-Year Prospect
Unless we somehow manage to solve all the mysteries of space, physics, and the universe in the next twenty years, astrophysicists don't need to be looking into how to sign up for food stamps. Tirelessly seeking answers to problems presented by invisible evidence proves that astrophysicists are a tenacious bunch.
Even though progress may be slow at times, the triple threat of new equipment, bright young minds, and input from related fields renders this branch of science relatively safe from extinction.
If you're looking into this field, you probably trust nothing more than cold, hard facts, so without further ado: predicted growth this decade for astrophysics jobs is around fourteen percent by 2020 (source).
The questions astrophysicists are asking today are tough ones. There's also a limited amount of evidence available for invisible oddities like dark matter and wormholes, so there's a lot more math to be done before we can prove anything. The more we come to understand about the universe, the more questions are raised about its true underlying behaviors.
Simply put, there's no end in sight as of yet to the chain of questions about what makes the universe tick. It's up to you to figure it all out—and then explain it to us, because this stuff is way over our heads.