I am amused by this general punditry about a dual OS/dual hardware strategy. Yeah, that has just about worked out for everyone who has tried it.
What you are missing is the rumored ability of QNX to be able to run Android apps. RIM may already have the dual strategy in place - they might run BB on Pro phones which can run Android apps and they can run QNX on Consumer phones which can also run Android apps. For the user - it's Android, not QNX or BB.