^^^Well given that I grew up in the area, I do know a lot of people my age there. Most of my friends seem to prefer the beach lifestyle. Maybe my personal social network is an anomaly.
Also, while I commend Orlando and Tampa, and even Jax for developing their cores/greater downtown areas, relatively speaking, the fact remains that no city in FL offers a true urban lifestyle, and it is likely that outside of micro-areas of Miami/Miami Beach, no city really will. I know relatively few people who move to FL from other cities/states, it just isn't common in my social group, but those that do all seem to migrate to the beachy areas, (particularly in S FL/Miami Beach).
Also note that Orlando doesn't have a beach as competition to its downtown, and that as far as waterfront goes, its downtown has lakes. Tampa is likely a better comparison. And there is a slightly different setup there - Pinellas, where the beaches are, is not the job center of the region for professionals. Inland Hillsborough County is, and traffic/time to get to/from beach in Tampa Bay is substantially more than in Jax (maybe by a factor of at least 2-3x?). That makes "living at the beach" and working a white collar job in Tampa/Westshore/suburban Tampa less attainable in Tampa Bay than it is in Jax, where the majority of such jobs are a 10-15 minute drive in from the beach.
And take my perspective or leave it, but if I moved back to Jax, it will have been after living in several large cities/urban environments. I won't be moving to Jax/FL for a small dose of "urbanity" but I could see myself moving to an environment I've never lived in/never had the opportunity to - the beach.
Note that LA actually has a similar dynamic - aside from Pasadena and a few other intown areas that for the most part have kept DTLA going, by far most of the desirable communities are at the beach. Having a bunch of friends down there (and I'll be down there this weekend), I could see myself living in Venice or Santa Monica, easily. So long as I work nearby or at furthest, in Westwood/Brentwood/Century City/Playa Vista. Which is why most of the professional jobs in LA are actually among these areas, not so much DTLA. DTLA is making a huge comeback, but it's at the center of a region of 18 million people and has a lot more to work with than DT Jax. Even so, it's been a struggle there too.