The problem for BB is they didn't build an empire of the willing. Apple and Samsung did. The backbone of BB's success was that it was sold to enterprise, and given to users with little choice. The consumer chosen market of BB didn't hold up to competition. Apple at least is still holding their own--certainly they are profit-wise.
As for 3rd place I would say that has a lot riding on how much MS is willing to throw into it.
Michael
I'd disagree with that. Yes BB aimed at enterprise first, but customers had other smartphones to choose from - Nokia had Symbian S60 and Microsoft had Windows Mobile which HTC and Samsung used at the time. But most of them chose BlackBerries because the brand was popular, the devices were seen as a status symbol, and people liked the convenience of the amount of connectivity BBs offered.