They're only worth that much if they're a viable contender in the phone/mobile wars - without continued products they're worth about as much as their patent portfolio, which is substantial but not that much.

Having reluctantly been convinced to try the BlackBerry passport recently I have to say I'm very impressed with the work BB is doing right now. The new OS is fast and snappy in a way only iOS can match, and even the most recent Androids can't dream of. They are innovating in both UX and typing in interesting (and IMO mostly successful) ways - I'm convinced that if it weren't for the stigma of sitting on their asses doing nothing for years about the smartphone revolution that these phones would be selling better than they are.

At this point the associative value of BlackBerry to quality - in the eyes of consumers anyways - may in fact be negative.