I'm pretty sure that their OS was one of their main reasons for flopping since nobody was really caring about making apps for BlackBerry
I had a curve before I got an S4 and the App Store was incredibly tragic. But then again its flagship at the time wasn't touch screen like apple or Samsung.
I'm surprised they held out this long, to be honest. Blackberries will go down in history. I remember when they were the phone to have. They were definitely second-to-none whenever it came down to physical keyboards.
It was bound to happen. I still used BBM on my Samsung until earlier this year because it was a great way to avoid giving away my cell number to be contacted. I removed since it occupies a hell lot of space.