Quite seriously, if Apple would release iMessage for Android and PC, BBM would be dead in the water. The only things going for it that I can see are the reputation for solid messaging by BB, and the cross-platform availability now. Thing is, I can't see myself installing BBM on my iPhone.
Since BBM is a free app, I'm not clear how BB plans to monetize it in such a way that it could save the company. Bottom line from where I'm standing is that BB screwed themselves on the hardware front with a string of bad decisions (with hindsight, of course), and since that's most of their income, they're in deep trouble and I don't know if they're recover. And if they go under, then what for BBM anyway?