This is great advice and I've seen it work for a few people. (Not specifically for cybersecurity.)

The short version is when people can ease sideways to a completely new role at their current employer. The longer version involves getting a new job doing the same thing, but at a company that does a lot more of the thing you want to do. Initially you do the thing you were doing before, but there's more opportunity to shift sideways when you get a good rep.