There is, in my world, two larger questions:
1) Can RIM survive as a hardware/software developer? This is a point I try to make: RIM does not have the resources of Apple, which is the only other company left standing that is a strict "in house" mobile provider. They have the money and the HUGE fan base to cover the monster investments it takes in R&D to develop the iPhone, test, produce, ensure the supply chain, market it, distribute it as well as all the investments for the software development, updates, and support. There is no way you can put a single dollar on these rising costs. Even Apple is starting to get criticized for falling behind and becoming stale. RIM does not have the luxury of the cash flow of Apple. Let's not forget that BB10 became so important due to RIM falling behind in the first place. Let us not forget how many times RIM has delayed BB10. It does look like they are doing this launch right, and that BB10 will be a nice OS. But- can they continue to keep up with the frantic pace of mobile? In a year and a half will they just fall back again, unable to keep up with the innovations of other companies? This is RIMs challenge. MS and Google not only have OEM's taking care of the hardware development and supply chain costs, they are both huge companies with many ventures with many other revenue streams flowing in. BlackBerry is it for RIM. While I expect CrackBerry loyalists to make BB10 a huge success in 2013, I find that scary for their future.
2) Is there room enough in the mobile market for more then 2 or 3 OS's? If so, then this is a unimportant question. I personally think that at even a 70% market share for iOS and Android leaves plenty of sales and room in the billion dollar industry that is mobile for both RIM and WP to thrive. The third place finish is only really important if you believe there won't be enough room for a fourth OS.
I am very, VERY excited for BB10. I love competition and choices. No, I am not planning on leaving WP, but I accept that it is silly to close off yourself to options. Right now, I am 80% sure I will be a WP 8 user (On my beloved Focus S WP7 right now, no hurry to leave it), with a 10% curiosity to BB10, and a 10% open mind to Android as both ICS and JB has improved it performance tons.
I am cheering for all 4 OS's to survive.