It seems that just about every business has that one element that everybody swears is too big to fail, then it goes either completely belly-up or its core dies. It always happens in a slow, painful decline that surprises nobody except the people who cause it by continuing to do things the way they always have as the market shifts around them and they stay stuck in their ways. The PC industry has IBM, for example, and the game industry has Sega. The newest name to join that list is smartphone old hand BlackBerry, who recently rebranded as a software company and will now be selling phones designed and crafted by others with their own software.
Long the king of smartphones, BlackBerry ruled the roost from the earliest days all the way up until the advent of the big-screen, touch-based smartphone that Apple ushered in. While there had been touch-based smartphones before, and fairly well-made ones at that, Apple popularized carrying a touchscreen-equipped computer in your pocket, and made the smartphone a must-have item. It also influenced the course of development for Android by changing the market just in time for Google to change course from their early prototypes, being very BlackBerry-esque and controlling like miniature laptops, to eventually arrive at the touch-based HTC Dream.
For a good while, BlackBerry retained a huge chunk of their loyal user base who were hooked on their secure, business-minded software and sturdy hardware with great keyboards. This model, of course, couldn't sustain them forever, and the fact that they never fully realized this until it was too late was the main reason for their downfall. Early attempts at touch-based BlackBerry smartphones largely fell short with consumers and business users alike, and even the Torch, which seemed made-to-order for the current market, and the well-made, well-specced Z10 never made much of a splash. By the time the Priv touched down, BlackBerry needed a miracle, and in a world of bleeding-edge specs, Nexus going mainstream, and hardware keyboards breathing their last, it wasn't enough.
While the famous BlackBerry keyboard' longevity is somewhat justifiable by virtue of just how excellent it is, it was not the only case of BlackBerry clinging to vestigal technology, or tech that would soon become outdated and even notorious. For example, they long supported Adobe Flash wholeheartedly, even when most of the internet and mobile communities were calling for its downfall; waiting for a processor that could handle Flash well is a big reason that BlackBerry didn't compete in the hardware wars in the same way as other manufacturers of its time. The fact that a good processor for Flash content was not available until Flash was on life support showed just how foolish it was for BlackBerry to sing its praises and shape their business around it for so long. The famous BlackBerry Messenger, or BBM, stayed exclusive to BlackBerry's hardware much longer than it should have, despite the fact that cross-platform messaging apps were becoming full-fledged businesses down the years. With this app being the main thing that made BlackBerry popular among non-business users, aside from that insanely good keyboard, porting it could arguably have been viewed as admitting defeat for the BlackBerry OS, in its tenth iteration at the time of its death.
A number of different factors combined to put BlackBerry on the path to decline that they went down, but one of the biggest factors was that their core business model's target customers were shifting gears around them and they simply did not want to change things up. Had BlackBerry embraced Android more whole-heartedly earlier on, or skipped the Priv and given people a true BlackBerry with Android on it, like an Android version of the Passport or Classic, their hardware division may not have had to go, or may have at least declined a lot more slowly and gracefully. As it stands, though, things are not all bad for BlackBerry; much like SEGA, they're finding a decent enough amount of success in the software market to keep going, and their signature super-secure, super-stable, super-clean software experience translates pretty well to the modern Android hardware that they're now forced to admit the market prefers over their own.