ok...my final point on this issue...
Density is a relative term....many cities, such as Washington, Baltimore, San Francisco, Seattle, etc. have not expanded their boundaries in decades (mainly because they can't)...most of these cities have run out of undeveloped land....as such, they are forced to concentrate their growth on redevelopment and densification.
Jacksonville, on the other hand, has tons of available land still....consolidation has generally been a positive, but this may be one down side.
Or you could take the view that the suburban development would have happened anyway (which it has in every meto area) and through consolidation/annextaion, cities like Jacksonville are able to keep that growth and wealth inside their boundaries.