Sure seems that way. Some leaked documents from Bell Mobility show that BlackBerry 6 isn't set for release on other capable devices until 2011. While Bell is set to release the BlackBerry Torch 9800 anytime now, the newly announced BlackBerry Curve 3G nor the BlackBerry Pearl 3G will get it right away, let alone the previously released BlackBerry Bold 9700.
As we've seen in the past carriers are often terribly slow to update to new OS' which, for customers is never really a good practice to see happening. While this information only gives us a look at Bell, it could be rather indicative of other carrier plans as well. Just look how long it took AT&T to release OS 5.0 for the BlackBerry Bold 9000. As BlackBerry users we always want to have the latest updates and that often means relying upon leaked OS' or using OS' from other carriers that are more liberal with their updates. Truly hoping Bell decides to change this plan, in the long run it's not great for their customer base to be stuck on an older OS.