That's a very dangerous career path though. If that legacy system gets replaced you are usually out of a job and job search is hard with outdated skills.
To give you an idea of how reluctant they are to replace things, some equipment in the manufacturing industry is over a century old and still in continuous use. They will certainly be extremely unwilling to get on the "upgrade treadmill" that seems to be getting faster these days.
Also, problem solving and creative thinking are never outdated skills. ;-)
That's a very dangerous career path though. If that legacy system gets replaced you are usually out of a job and job search is hard with outdated skills.