Most people can't afford to live on Kauai on a GS-12 salary, assuming they can even find a house for their family there.
A lot of people think HI is the dream place to work and live but there are so many sacrifices one has to make that it actually culls the herd pretty quickly...more than I understood at the time I was trying to do everything in my power to get out there. Even removing pay or housing from the equation, distance from family, especially when kids are involved, becomes a huge sacrifice for many people that they're not willing to make.