20-Year Prospect
As long as there are amphibians and reptiles, there will be a need for people who understand them. With growing human populations, climate change, and constantly evolving viruses intent on throwing their loud and rowdy infection parties despite our frequent complaint letters, you can bet that need is only going to have grown by the time you're out of school and in the field.
Barring some sort of massive extinction event of dinosaurical proportions, this will be a safe field for years to come.