Proximity to the port of Norfolk may have been the deciding factor.
Proximity to Norfolk is the likely answer. Most of DC bound cargo actually goes through Baltimore. Due to the efficient rail system, much of the Norfolk cargo goes to Chicago, Ohio, and even points West. I am surprised they picked Richmond over Isle of Wight and Suffolk, but I’d be willing to bet these centers will be on the new US 460 limited access toll road they are building from Suffolk to Petersburg, which is designed to take the port traffic off of I64 and the Hampton Roads Bridge Tunnel.
BTW I worked 3 years in Norfolk as an export service manager and import traffic for a major steamship line so I know what I am talking about regarding where the cargo is going. Not just spewing drivel.