But none of the ground floor space was ever filled. It's been 20 years now. I think they converted it to offices? At point, they had community art displayed there.
I think you're confused; there haven't been any retail vacancies on Avery St. for some time now, once Emerson College decided to fill in the last one (which admittedly, was quite large!) with its rather avant-garde (said objectively, not smirkingly) art gallery:
http://www2.emerson.edu/urban-arts/media-art-gallery
The gallery went into the street-level condo of the Mason Pl. affordable apts, which isn't even owned by Millennium, for what it's worth.
Do a virtual walk down Avery St. and you'll note no vacancies...
All that said, there really aren't many retail condos on Avery to begin with: the Roche Bobois, the Ritz restaurant, Emerson arts gallery, the handicapped ramp to the cinema--realistically, only 3... (I don't count the cinema as "retail")