When I bought my T-Mobile G1 with 3G capability (in Februray, 2009), my wife's BlackBerry 8900 (the newest phone they made at the time, we got it a couple weeks after it was released), still only supported EDGE. This was a sign, to me, that BlackBerry was resting on it's laurels and not trying to advance itself. 3 months after the first Android phone was released (with 3G), blackberry was STILL releasing new phones with only EDGE support. Even if Android was basically non-existent, and the iPhone was still just a toy, BlackBerry should have been trying to keep up with modern technology and trends. Instead, they just kept releasing the same software and same phones (with slightly better graphics and a couple more MB of memory), but not really changing anything. When Apple and Google came out with OSes (and supporting phones) that were more capable (for the average consumer) and user-friendly, BlackBerry was left playing catchup.
This happens to the leaders in most industries. Look at Microsoft's failure to innovate. They're so big and have been #1 for so long, they can hardly come up with anything new. It took them 7 years to get Vista out the door after XP, and it was such a fiasco upon it's release it set them farther back than had they not released it at all (Linux and OSX are growing in popularity). People are violently opposed to upgrading from Windows XP. I don't recall such aversion when XP came out after Windows ME (yes, XP is better than ME, but Vista/7 is better than XP). People just don't trust Microsoft anymore.
BlackBerry was on top of the smartphone market for so long, they didn't even know what hit them when the iPhone and Android hit the market. Blackberry was left playing catchup, and you can't catchup if you continue to release products that are inferior to your competitors.