Some people prefer neighborhoods over sprawl, those people will always choose urban options. Some people raised in suburbs only know suburbs. let's hope we see more people come to Jax who want urban options.
There's a lot of movement in all directions. But what I have seen across many markets across the country is that there is often a reversal in mentality and wants depending on what one has been accustomed to, and thus grown tired of. Many people who grew up or have lived recently and for a while in urban environments (truly urban, which is not offered anywhere in Jax, not even remotely close) grow tired of that lifestyle, as it can be exhausting. They'll trade the pluses of this lifestyle for increased road traffic/longer commutes, often in a heartbeat, to get into a cookie cutter pristine suburban area such as this. This desire to trade out amplified exponentially with kids.
Lots of people who grew up suburban or have never given the urban lifestyle a shot and have recently heard all about it (maybe have friends that have given it a go) decide to move to an urban location/urban city, from a more suburban location/suburban city. Most of the young set in NYC, SF, and Chicago are indeed transplants, many of whom come from Los Angeles at most urban to random points of the south/midwest. I am actually a living example of this, and I can see myself wanting a quieter, more suburban lifestyle at some point in my life if I choose to have kids and settle down.
Jax is a bit more stereotypically "southern" in that there is a larger demographic of less traveled people. So there is more of an element of people sticking with what they know (Ortegans stay in Ortega, suburban people stay in their little bubble, and so on and so forth). This is perhaps not surprisingly more common in Jacksonville than many other cities. Therefore, it stands to reason that downtown has that as an exacerbated obstacle relative to some other cities.
Jacksonville also has a stronger competition with the Beach as a desired place to live and have an office and shop. Atlanta, Charlotte, Austin, and Nashville do not have a beach.