User blog comment:GodzillaMaster/Truly Extinct?/@comment-1221773-20111118214259

For my money, I think there was only one ship and one base, and all of the Collectors were destroyed at the end of ME2.

Could there have been other ships and/or bases? The possibility was never explicitly ruled out, but there's no evidence to support the idea either. The Collectors' absence in any recent ME media is, in my opinion, very telling.