Rural medical specialists are compensated very well. In my experience the bigger obstacle to getting those roles filled is more social, for example, unless you are already married the dating pool in a rural area is a consideration for new doctors, or if you are married and your spouse has a career moving to a rural area may require them to give up that career which they may not be willing to do. Cities better support dual-career households b/c they have a density of industries. Also - after 10+ years of school a lot of new doctors want to live it up a bit in a place with things to do and see.