Experienced cavers rarely or never hire a guide for the cave (only for the country they are traveling within) and that is even rare. I know a few cavers who organize trips to China or other parts of the world to cave and get to cave that way, but it doesn’t earn them a living. (Sure is fun though)
Careers that might involve some cave exploration, if you find the right job:
1. National Park Service hires cave specialists and they work at parks where there are caves in the park. One or two per park is probably all they hire. http://www.nps.gov/seki/naturescience/ca…
2. Hydrologists who specialize in karst hydrology may get to explore caves from time to time. These can be government employees (state) or consulting geologists who work on contract for government or companies that are regulated. http://hoffmanworld.org/dyetracing2/?pag…
3. University professors who specialize in karst science, karst hydrology, geochemistry related to caves, biogeochemistry related to caves, or some other field of research that involves caves.
4. CIA. I am only guessing at this one (plausible denial is required) but I would suspect that CIA or some military branch has hired a few people to explore, map, and remove bombs from caves in places like Afghanistan. You might not live long in this career, but it would certainly be exciting.