Because nobody has RIM devices anymore. They aren't selling devices. Developers aren't jumping on the BB10 bandwagon. Several major executive shakeups, Plummetting stock prices, and again: no developer interest.
I would agree with you about the drop in sales and in the share price, those being related of course. Also, I think everyone agrees, BBOS is old, antiquated, and dead. The executive shakeups were likely all related to this, and hopefully just a chance to clean house. I agree though, it's entirely possible they left because they don't see BB10 succeeding.
I would disagree about the lack of developer interest, especially with BB10. Most of the BlackBerry 10 Jam World Tour events are sold out, and have been sold out in a matter of days. There's are also a lot of open-source developers moving their stuff over to the PlayBook because of the ease of doing so. RIM has been pushing HTML5 on the platform, with a number of projects touting support for it (PhoneGap/Cordova, Titanium, jQuery Mobile, Sencha, just to name a few). I haven't even talked about the support for native C/C++/Python3.2, Adobe AIR, and Android apps.
Also, RIM is working hard to engage with developers. They've been very active via their @BlackBerryDev twitter account, and you can easily reach anyone on the Developers Relations team. Heck, you can e-mail Alec Saunders, VP of Dev Relations, directly yourself.
However, until the device launches, we won't really know what to make of this. We don't have hard numbers about how many developers are actually actively developing for the platform.
Let me turn it around:
What would it take to get you to buy a BlackBerry? What would it take to get you to develop for it?
