I think in the US, rather few people move somewhere simply because they think it would be nice to live there. Most people move somewhere either because they've gotten a job or hope to find a job there. My first long-distance move was to graduate school to study for a Ph.D. which is sort of a job. My other two moves were to places where I had gotten a college-teaching job. In each of those two cases, my job search had produced one job offer, and my previous job had come to an end, so I had no choice about where to go if I wanted to stay in the same kind of work. I simply crossed my fingers and hoped life would turn out acceptably well at my new location.
People do often move by choice after they retire from work. In the US, it's common for retired people to move from the northeast and midwest to the south (e.g. Florida or Arizona) to escape cold and snow in the winter. My parents and one of my aunts did this. One of my cousins moved from upstate New York to northern California (not far from Sacramento). I've lived in the south for many years already for work, so this isn't a factor for me.
Many retired people also move from expensive places to cheaper places, to stretch their pensions and savings further. This also encourages moving from especially the big cities of the northeast, to the south. My brother moved from the San Francisco area to Arizona after he retired, because he and his wife simply could not afford to live in the SF area on his pension.
My wife and I have both retired from our full-time college-teaching jobs, so we could move if we wanted to. However, we have no urge to do so right now. First, she still teaches part time and enjoys working with her long-time colleagues. Second, it would be a major hassle to clean out our house after living here for 30 years.
I myself would probably want to look at small to medium sized cities with a major university, for cultural opportunities and good medical facilities. For example, Ann Arbor, Michigan (where I went to grad school, but it has winter); Madison, Wisconsin (also has winter); Athens, Georgia; or Chapel Hill, North Carolina.
One kind of place where we definitely do not want to live is a large suburban-sprawl type area. We like living in a reasonably compact area where we can walk to at least some activities, don't need to drive far for the others, and there isn't too much congestion. My parents retired to southeast Florida (the urban strip that extends from Miami to West Palm Beach), and for many years we visited them there every year, usually staying for about a week at a time. We enjoyed the beach, but we didn't enjoy driving through miles and miles of busy highways to do almost everything. My wife grew up in the suburbs of New York City, and has no desire to live any place like that again. I've always lived in small to medium-sized cities, about 200,000 people maximum. Our current city is less than 10,000.