And that is where I think you are flat out wrong, maybe you have read more national press releases, or you see more attention for those cities on these kind of sites, but MANY metros under 3 million are seeing massive urban growth. Columbus can fit right into the growth of Louisville, Austin, or Nashville, you just haven't researched whats going on in Columbus, thus your only uninformed. And it doesn't stop at Columbus, Charlotte is under 3million and is seeing a lot of growth, Raleigh is, Indianapolis is, its not just 3 metros under 3 million, theres many growing metros in that range with downtown growth.
Columbus has condo tower infill all over the central city. Just because Columbus doesn't have one 62 story tall tower doesn't mean that the city isn't seeing a major downtown growth pattern. If you added up all of the other infill and smaller towers they would be of that same unit value of a 62 story tower. A 62 story tower is not the only sign of downtown population gain.
As do many other growing cities, from 02 to now Columbus' downtown population did increase by 1,000. Many cities around the US are seeing the same growth.
And this has happened in a lot of other downtown. I still don't consider these places the "most" booming downtowns in the US though. That still goes to the central cities of maybe Atlanta or Charlotte. I don't know if Austin's downtown construction is really enough of a boom, its still pretty residential based, a boom needs Corporate relocations, and new office, only highrises. I still don't think Louisville, Denver, or Columbus, although seeing downtown growth, are booming in downtown on all levels office, retail, residential, and at a massive rate nationally.
Here is a site with a pretty good run down Of Columbus' developments,
Central & Southeast Ohio Projects & Construction
Some Columbus central city/downtown infill that's been built since 02 or later
This condo tower is in the finishing phase, it sits in the Arena District
This is a 22 story condo tower, Miranova (on the right):
http://urbanohio.com/gallery/cache/Central%20Ohio/Columbus/Skyscrapers/IMG_1757.jpg_595.jpg (broken link)
And there's many like this in mid-rise category
Caryles Watch
http://www.urbanohio.com/forum2/index.php?action=dlattach;topic=1911.0;attach=3473 ;image (broken link)
And this is an example of a turn of the century mid-rise that is an office/condo redo, the building was empty for years before this remodel. There's many like this around downtown as well.
This is a condo infill in Columbus' Short North
And then you have massive infill projects, that take up whole city blocks like this one called the "South Campus Gateway"
The Arena District is sq. miles of urban infill that's based around Columbus' downtown NHL arena, its mixed use, and isn't proposed but was built totally out of scratch, minus one or two buildings that were a reuse.
Apartments to the very back, retail to your right, and offices above,
Cleverly placed Apartment infill in the Arena District, Arena Crossing
Office/retail infll on a park, in the Arena District
The arena
Residential Condos in the Arena District
OF course Columbus has many warehouse conversions on going...
This is the Buggyworks
Redone department store into offices, back downtown
60 spring infill
The Brunson Infill
Short North Infill
This is now condos/and apartments, its quite a large older building, was once a hotel
Now condos, rehab project
This one's actually a 70s office conversion
There is a lot of brown field rebuilding in central columbus, this entire mining site is now rehabs and a complete new build muilt-use project, there's a lot of this going on in central Chicago too, entire industrial site conversion is very interesting I think, there's several large projects like this going in central Columbus
Ohio Loft, mixed use
BEFORE
AFTER
And as you tell i have stuck to only some of what has been built, this is some of what's coming
Time Tower, next condo tower infill over 20 stories
http://cll.bizjournals.com/story_image/82939-400-0.jpg?rev=2 (broken link)
As you can tell the list can go on and on, I have barely scratched the surface of Columbus' urban infill of today, and it's the same with many other central cities around America.