I wouldn't expect a town of 30k (or even 100k) to have that many jobs for developers as it's a fairly specialized industry.
50 years ago you wouldn't find actuarials or design engineers in small towns either.
For the profession of software engineer, most of the jobs are in the higher salary bands there should have an outside impact on the average calculations.
For example, I looked and found a level 1 Software Engineer opening in Kansas City for 50K. That actually seems pretty good -- the median house price there is 120K. Here in Portland it's 345K, and entry level engineers aren't getting 3x the salary. More like 80K or so.
This actually sounds kinda like a good reason for moving to the midwest, assuming you like everything else about it there.