There are many considerations here: one’s age, occupation, income, family status, foreign language abilities, potential destination, etc. Clearly moving to Central Africa would be unwise but what about moving to a country notably better in terms of happiness? One could consult the UN’s World Happiness Report where the US was ranked #17 and move to a happier country like Denmark or Sweden.
But it isn’t that simple. If one didn’t speak the language of the destination country then one would be isolated. So for our purposes let’s consider English-speaking developed countries, the kind that a US citizen might reasonably consider like Canada, England, Australia or New Zealand. Suppose you were a young married couple with a newborn considering such a move and you could get a job transfer to one of these countries. Would it be wise to do so?
In some respects it obviously would. The chances your child would be the victim of sexual assault or gun violence for example would drop dramatically. And if you were concerned about economic equality or a strong social safety net, all of the above countries would be more aligned with your values than in the USA’s “winner-take-all” society. Still, suppose you had to leave extended family in the move? Would it be worth it then?
Consider the following thought experiment. Suppose you lived in one of the worst countries in the world surrounded by a loving family. Now suppose you had the chance to move to Denmark, the world’s happiest country, where you had a good job waiting. Suppose also that you spoke Danish fluently. In that case moving to Denmark is an obvious choice, and your loved ones would likely encourage you to move.
Now suppose you had the choice of staying in a country where your loved ones or moving to a country you thought was a bit better to live in but to which you family could not move. In that case most would probably stay put. The benefits of the support and comfort of grandparents, aunts, and uncles, would probably outweigh moving to a slightly better country. Of course this might depend on how often you could see your extended family. If you could see them quite often it makes more sense to move than if you could only see them occasionally.
Of course any calculations on such matters depend on whether you are a single, married, married with children, etc. For example, if one has no family then the choice is pretty straightforward, go to the best place. Or if one was married with children and could bring their family but not their extended family, that is much better than bringing no family at all.
Of course all of this depends on your best estimate of a country’s future. In the case of the USA, increasing social corruption and political dysfunction make the future seem bleak to me but, on the other hand, it is nearly impossible to predict future trends. In the end we make life’s decisions with imperfect information; that is the state of the world that we must accept. And all advice is imperfect too.
With that caveat in mind I would advise all young people to seriously consider emigrating from the US if they have the chance, especially if all or some of their loved ones could accompany them. After observing trends over the last 50 years, I believe America will increasingly become a worse place to live, except for the very wealthy. But I could be wrong.