We jabbered about The Plex during its' construction: http://www.brooklynian.com/discussion/16626/958-nostrand/p1
As it neared completion in 2012, it was clear to me that the developers had a long range focus, IE they were constructing the apartments and commercial space for tenants they believed would live in the neighborhood several years AFTER it was to open.
The developers seemed to have deep pockets and seems to factor that the apartments would take a while to lease up, and have left the ground floor vacant until tenants that matched their price point and brand arrived.
Despite today's stock market drama, I believe one or more tenants for the ground floor will soon be found.
The neighborhood is ready.
The ads have been placed: http://www.cityfeet.com/cont/ForLease/LN18639455/958-Nostrand-Avenue-Brooklyn-NY-11225