I'm so glad that the example of Asheville has popped up on this forum. We visit Asheville regularly and over the 40 years have seen dramatic changes in their downtown. Sure, it's not as big as Jax but they have had some very forward thinkers who were willing to sit at the table and put time and money into a restoration and renovation of their central area.
In the 1960-70s, the place was a mess. Pollution, air and water, and a propensity for tearing down much of their Art Deco heritage. Citizens revolted demanding a new vision for downtown. Two big money men started renovation of downtown buildings with the idea of attracting artists, non-profit groups, university students, and urbanites. They saved some beautiful old buildings and helped the city to get grants to landscape, redo sidewalks, lighting, parking. The town quickly filled up with small business such as antique stores, family owned business, ethnic restaurants, folk art. Some of the factory buildings were converted into malls and a huge art and entertainment center was restored. Old buildings were converted to condos and offices for non-profit groups.
The point of Asheville which I think could teach us is that sometimes you have to start small - sort of organically in the Jane Jacobs mold. Big super stores will never make the investment in center cities because their kind of business depends on following a proven model not flexible enough for urban areas. I was in Asheville two weeks ago on an early Sunday morning. The town was alive. People were coming into restaurants to eat Sunday brunch and walk around looking in shop windows. Shopping in Asheville is a great experience if you want unique items, personalized service, and pleasant town walking. Asheville is beginning to have success problems - vagrants looking for handouts, wealthy developers wanting to tear down old buildings, litter, graffiti.
Seems to me they will handle it.