I work in an industry with useful, important, specialized, but unsexy technology.
PCM Audio, Multicast, lots of analog connectivity, arcane binary protocols (even widely adopted and interoperable ones), lots of manufacturer specific protocols too. Windows and RHEL. We've only just barely figured out what Web 2.0 is, Javascript based UI is new for us. We also do a bunch of embedded development, RTEMS, now Linux, other shops have some VxWorks too. Plus lots of development on just DSP code. This isnt just us I'll note, its my whole industry.
Technology in our world moves very very slowly. We provide decent wages, good benefits and a no requirement for overtime, but it's not sexy and it's not the way the rest of the technology industry is pivoting. We provide solutions that are reliable, and must work, but dont need to serve billions, just hundreds.
Also, as a deployment engineer it takes someone new into my role, about six months before they understand enough of the system to work unaided. It's not that we cant find developers - its that finding people who understand our industry is hard, and even if we hire someone who isnt in our industry, it does take six months or so before they can be productive. The larger issue is, they dont see the technology work on as a good stair-step on their career progression, so they dont wanna work here.