There was a good discussion on this at Mike Blumenthal’s blog. General consensus was that Google removed them while trying to fix how they were improperly applying Authoritative One Boxes for some searches.
Today, I’m seeing the 7 pack back but only when the search contains a word like “in” or “near” within the search phrase. So you get a 7 pack on “web design in Nashville TN” but no 7 pack on “web design Nashville TN”
1) Google is slowly rolling out the 7 pack on these searches & it’s just not fully implemented.
2) Google decided that some searches should not have geo specific results ie. web designers and ad agencies are much less dependent on their local area vs someone like a salon or a bathroom remodeling contractor.
I’d say the the 2nd option is much more likely. While we may see it change again in the future, searchers looking for services like websites, advertising & marketing are more likely to consider an out of town provider. OTOH, I think most businesses are more comfortable working with a provider in their area so maybe we’ll see some additional boost to local businesses.