There is a logical explanation for SOME of the little towns that have stations that make you ask: "WHY????". As it became harder and harder to find a place on the dial to put a new station to be the 2nd or 3rd station in a desirable town, my memory is that the FCC (in it's wisdom?) decided that communities that didn't have their own radio station should have first shot at any available frequencies. (Maybe even being willing to bend the rules a little bit to provide a "first service".
I could almost see "shoehorning" stations in, in the manner that you suggest (and it is now also happening here in Nashville on FM), but then the question becomes, what about when the small AM station in that town goes off the air, and there is no other remaining station with that particular town as a COL? Fairview is a fairly decent sized town (recently got a Wal-Mart, I think, or is about to get one), but apparently cannot support a radio station, no matter how small.
I'm not familiar with White Bluff. I see that it now gospel. Was it from the beginning? What makes it different than some of the other non-county seat towns you listed is that it is suburban Nashville. Had I been looking at the maps without this conversation, I would have simply assumed, "Oh, someone wanted to grab a bit of the Nashville market, and by claiming "first service" policy, was able to get this thing licensed." My second guess would have been: "Oh, someone wanted a religion station and they didn't care that there was no significant supporting retail market." (Or they knew so little about broadcasting they didn't know that retail is the life blood of small town radio.)
They came on the air (surprise, surprise) in 1982. I first became aware of them in 1993, when at that time, they were alt-country, playing a lot of stuff on indie labels. Their overnight programming was real high-tech: a six-CD changer on repeat all night! I believe that their owner-manager at the time wanted the station to be a place where up-and-comers could get some airplay and exposure. It must not have worked, because only a year or two after that, they became gospel, and I believe that they have been ever since. At the time I became aware of them, I had just left WDXN in Clarksville, so was considering applying at WQSE, but I seriously doubt that I could have ever made a living on whatever they could have paid me. Ironically now, they are the geographically closest station to me, with studios just 10-11 miles away from me at most, but I did not live here in 1993, and was in fact in the process of moving away from Clarksville at that time.
Why are you, living in Atlanta, so interested in radio here in the volunteer state? While WQSV was off, I briefly picked up a sports talker at AM 790 coming from Atlanta, and mistakenly (as it turned out) assumed that WQSV's new owners (who were going to change the calls to WJNA) had put the station back on the air. Meanwhile, an engineer from the opposite end of the county (Pleasant View) posted that he was receiving a sports talker at AM 790 from Louisville at about that same time.
Now I read (on the other board) that Chris Lash is taking WMAK-Linden back to his original oldies format. Must be tough to program an AM station (particularly in a rural area) these days. I don't recall any mention of sister station Hank-FM, so it must be remaining country.