I just read this great article about reverse migration, and at first the term itself was a little confusing. In short reverse migration is the study of seniors who are migrating back into city life instead of coastal living.
In many ways it makes sense! As a young person people are drawn to the city for the abundance of things to do. As a retired individual you also look for places that give you as many options as possible. The big difference is that stereotypically the older generation has more disposable income and can really enjoy the finer things that a metropolis has to offer.
Living in a big city, can be very different for those who count every penny to those who have planned their golden years.