I've lived in a very poor area of the US for 16 years, and I'm not sure I'd recommend moving to my former town just to save money. Certainly, you gave some examples of places that may contradict my experience, but do you have personal experience living there and not just visiting a short stay? Normally a place that has great amenities wouldn't be so cheap. Typically the main industry that made it a city has gone away and there is high unemployment, drug use, nothing to do, etc. If it's been revitalized, I would think property prices would be higher, so I wonder want makes Hot Springs an exception to this general trend.
These two suggestions are sorta like resort towns, with the large lakes generating revenue for local businesses through local tourism and retirees spending their cash. Either place is great for anyone who enjoys boating, fishing, scuba diving, hiking, camping, mountain biking, white water canoeing/kayaking, etc. The much bigger Hot Springs additionally has an active downtown night life, a lot of history, a racetrack/casino, some very nice restaurants, microbreweries, the only sake brewery in the US that I'm aware of, and various festivals/cultural events.
Each place has other industries and neither is an industrial-bust town. During recessions, the people cutting back on local tourism are replaced by out-of-state tourists looking for something cheap to do. For a WFH employee or retiree, each location represents a way to retire on very little or sock away a majority of one's paycheck, while not getting bored.
That said, if you buy one of these cheap houses is it likely nobody on your street has a college degree? Yes. Are lots of the people religious authoritarians and racists? Yes. But is finding your tribe in such an environment a much easier adaptation to make than moving to South America, where you don't even speak the language fluently? Absolutely.
In efficient markets, things which are cheap are assumed to be cheap for a reason. However I just don't see it when it comes to regional differences in cost of living. It might cost twice as much to live in Phoenix, AZ as it costs to live in Branson, MO, for example, but is it really twice as good to live in a place where the heat kills hundreds of residents per year and water supplies are near emergency levels? Is Newark, NJ built upon a fountain of happiness that justifies it being two or three times as expensive a place to live as Hot Springs, AR? Is it better to live with six months of winter and hour-long commutes in the Chicagoland area, or to live in four-seasons of Heber Springs, AR?
What exactly does one buy with the corporate salaries available in HCOL areas? A big house? A houseboat? A couple of new cars? College for the kids? Well, middle class folks are purchasing those things in LCOL areas right now. It's less "you get what you pay for" and more like completely different economies with different inflation rates. I see no evidence that people in one or the other type of economy are actually happier.