Nah, not really. Sure, iPhone users will be on iOS 6, but how many people will be on Jelly Bean? Less than 7% of Android users are on ICS, with over 60% still on Gingerbread. And will Windows Phone 8 even be out by Q4 2012? MS hasn't provided a firm timeline on that, nor for Windows 8.
ICS is mostly theoretical for Android, as Gingerbread is still the reality with no guarantee of getting an update.
Windows Phone 8 is definitely theoretical for Microsoft, no consumer has a WP8 phone in their pockets right now.
iOS6 really doesn't bring a great deal to the table, it's an incremental upgrade over iOS5, which is an incremental upgrade over iOS4 which is... bottom line is iOS still isn't where webOS 1.0 was at a couple years ago, and BB10 will be ahead of that.
Most people with Androids will have been stuck on GB for so long and haven't got any upgrades that they'll have had a miserable experience for a while and will want to switch. Some will want to switch to iOS6, some will want to switch to WP8 and some will want to switch to BB10. That's to say nothing of those not even on GB yet. Less than 7% on ICS, with the miniscule amount on Honeycomb means the other 25% aren't even on GB. Even if we say 2/3 of Android users stick with Android, they'll probably want to try other platforms equally. If they liked Android because it was Linux based, the QNX base of BB10 will appeal to them. If they liked Android because it's not Microsoft or Apple, BB10 will appeal to them. It's fairly reasonable to say 8% of current Android users will want to switch to BB10, and that's more than are currently on ICS.
RIM won't be doing stellarly, and they definitely have issues with getting OS releases out on time, but they won't go under either.
The word 'Pentaband' means '5 Bands', from the Greek word 'pente' meaning '5'. For a phone to be pentaband it has to support 5 bands. If the phone has AWS support, it doesn't automatically mean that it is pentaband. The reason Wind and Mobilicity users like pentaband phones is because the reverse is true. We're not the only ones who like pentaband phones though, so please stop referring to phones that work on Wind and Mobilicity as pentaband. It causes unnecessary cofusion.