"Cui bono?", "to whose benefit?", is a question that should never be far from mind. It is rarely the case that the loudest threads in our grand, connected cultural conversation represent the best, the most useful, or the most virtuous of what is possible. That is just as true in any subculture as it is in the mainstream: follow the money and much becomes clear.
Longevity hotspots might not be a term familiar to you, but Blue Zones might be thanks to a fair degree of publicity for that latter term. They mean the same thing, but the latter is a brand rather than a description. A small industry associated with this brand is devoted to promoting the idea that some parts of the world exhibit pockets of exceptional human longevity. It is convenient for various businesspeople to act as though this is proven beyond a doubt and that the root causes involve aspects of local culture, diet, and lifestyle that can be packaged up and sold. So the world goes on: this sort of thing is a textbook example of how small science projects on minor aspects of human longevity can spawn commercial monstrosities set on muddying the waters, promoting myths, and profiting from the credulous.
It is by no means certain that longevity hotspots exist in actuality, or at least not in the sense that Blue Zone business ventures would like you to think, but those most interested in carrying on a dialog on this topic - i.e. marketing folk involved in tourism, diet, lifestyle coaching, and so forth - don't really care to hear that message. Nonetheless:
Estimates of per capita centenarians in a Utah population varied between one per 12,864 and one per 4,675, depending on the data that were used, the population assumptions that were made, and the boundary limits that were employed. In general, caution is warranted in claims about the existence of longevity hotspots.
Performing any sort of statistical study on human populations in a given geographical area, even on something as apparently simple as age, is enormously complex. People move and data is ever incomplete or outright false. Some locations attract the wealthy in large numbers, a demographic already well correlated with greater life expectancy. When a region in the US with good demographic data can produce a threefold range of results for a simple population question, one has to wonder about the accuracy of other studies - and the smaller the group the less helpful that statistical procedures become.
This is not to say that there is nothing to be learned by comparing different populations with different lifestyles, but I would be extremely surprised to see the end results be anything other than additional support for the value of exercise and calorie restriction (and derived measures such as body mass index). These line items strongly correlate with health in large statistical studies.
Neither exercise nor calorie restriction will let you reliably live to see 100, however. The only thing that can achieve that goal is significant progress in new medical science. Longevity hotspots are, like so much of what is discussed in relation to aging these days, nothing but a sideshow - something that occupies time and energy and attention, and all to no good end. That the data is most likely flawed and what little science there was is now largely buried beneath an industry that strives to make money by promoting magical thinking and ignorance just makes the joke a little more black.