My last gig was at a place where a guy basically wrote his own job security by reducing a 1hr 40min JS build pipeline down to 2 minutes with Nix caching.
It's implied because it's true. Throw away the content-adressable cache index and you're back to 2 hour development velocity, so the Nix guy probably gave himself a decade and a half of runway for a workload that mostly amounts to periodically running `nix flake update` and shuffling around version hashes.
We already saw this same trend happen where "the CMake guy" or "the Xcode guy" gets wheeled in to solve their domain-specific issue in large enough orgs. I was impressed by this guy's initiative to carve out an equally indispensable niche.
In truth, the "job security" thing is often as much a matter of personality as it is explicit strategy. The "XYZ guy" often becomes that person simply by being someone who is stubborn enough to tackle integration problems most people would rather avoid, and by being willing to deeply embrace "RTFM".
To say they've established "job security" can sometimes seem like a cynical read on their roles, but I think it's always good for teams to have a few devs with this sort of personality.