They aren't falling behind... their problem is that everyone has caught up to them in terms of features and even surpassed them in terms of usability.
RIM has a large segment of the current smartphone market. Their hardware is good, but their OS is last gen. They are trying to keep up.... they now have two touch-screen phones, but unfortunately only on one network.
The Iphone being exclusive to AT&T prevented it from making any huge dents in RIM's market share, but google offering android to any/everyone who will pay for the 'instant-smart phone service' has turned every single handset manufacturer into a viable competitor & serious threat.
In the olden days, phone makers had to spend bucks to develop both the hardware and the OS. Data features like web browsing or email required investing more money in tailor-made application which only a small segment of users were interested in.
RIM gambled that offering a robust data service to users that freed the cell phone companies from having to manage internet servers would be a winning solution. It was. Cingular sold you your phone and paid a portion of your data fees to RIM for managing and pushing your data from the IP cloud. They also offered messaging features and add-on applications that no one else was at the time. A few people copied their phones. but didn't have as much success.
Then the iPhone came along. The feature-set was meager compared to a blackberry, but it had a user interface that was 3-generations ahead of anything anyone else was offering (iPhone STILL has the best interface today). All of a sudden you didn't have to use a trackball or tiny qwerty keypad to get email or movie showtimes. Then the app store came a long and let the iPhone do things that blackberry devices couldn't.
RIM took notice and developed the Storm. A large display device with a touchscreen and lots of bugs.
Phone makers who weren't RIM or Apple grit their teeth trying to balance coming up with robust software, with lots of features, slick interfaces with hardware that would run it decently.... while trying to keep the costs of the devices low enough to compete.
It was slow going. There was windows mobile, but it was just as buggy as their desktop software. Samsung even tried their hand with their own OS on the Instinct.
Then HTC, mostly known for selling text-messaging phones took a chance on Google's android with the G1, on the smallest of the big 4 providers. It wasn't as slick or as fast as an iPhone, but it was a low-cost touch-screen smart phone that offered more basic features than the iPhone right out of the box.
Handset makers quietly took notice and started running the numbers on the costs of developing their own software vs dumping their money into hardware and letting google handle the lower level software side of things.
One year after the G1 was released, there are 6 more android phones available (MyTouch, Hero, Clique, Droid, Eris, Behold), and more in the works.
RIM is just one company. The storm was their biggest departure from their proven OS, which they have tried to refine with the Storm2. Even if the Storm2 is great, it will be one smartphone by one manufacturer among the iPhone, 6+ android phones, and a couple of windows mobile 7 phones.
The playing field has been leveled and there is way more competition now. RIM will lose market share going forward. What they should have done is offered to license their OS and data services to other handset makers before Google did.
As innovative as RIM is, they can't hope to keep pace with Google on Google's turf (the internet). Best to cut costs and try to find a niche to exploit that no one else is filling.