It's true the writing off of Downtown Jacksonville as a place for up and coming Millennials has many, many authors I want to bring up three things not often talked about that together create obstacles to DT growth unique to Jacksonville.
1) CONSOLIDATION Nothing new with CBD businesses bolting for the suburbs, but with a consolidated Duval County that exodus has been super-sonic fast. And although some have kept a presence DT, there expansion plans wanted nothing to do with it. With consolidation, not only were there no incentives for these businesses to stay or invest in the core, the powers-that-be practically helped them pack! The end results are that Jacksonville now has one of the most de-centralized job markets in the nation giving little incentive for anyone to live downtown.
2) CONNECTIVITY Many downtowns face the typical barriers that hinder it's development: Suburban flight, severely reduced manufacturing base, interstates through neighborhoods, etc. but I'll add one that has (unintentionally) hurt DT Jax - The St Johns River. Yes, the mighty St. Johns that's supposed to be one of our greatest assets has over the years hurt DT because for many it has acted as an unofficial demarcation line for good Jax/bad Jax. Ask anyone who moved here in the 80's and 90's what they think of the Northbank compared to the Southbank. And notice how most of Duval's development have been East and South of the river. True, these negative views are misperceptions, but that's part of the uphill climb of public opinion DT Jax has to deal with.
3) EXPERIENCE I think this is the big elephant in the room when it comes to attracting people Downtown. Most people in the area have kept negative views of Downtown Jacksonville because a lot of them don't know what it's like to live in any other way. Think of everyone who went on to college graduating from a regional high school over the last 40 years: What percentage of them got their undergraduate degrees at Georgia Tech, Tulane, SCAD, College of Charleston, or any other "urban" campus? If you spent years of your formative life appreciating close-by downtown amenities, not having to rely on your car, and having no major issues living next door to communities good and bad, you'll more likely consider downtown a viable living option - even having lived through a university "bubble". This lack of that type of experience by young people is compounded by Florida's university system's scant options for this type of college life.
I'm glad to see the tide turning as far concerning opinions of downtown revitalization, but because of these and many other reasons, Downtown Jacksonville has a lot more setbacks undermining its ability to catch up.