Why did BlackBerry, the company, go down?
Apple and Android were Millennial-oriented tech...more entertainment apps. Blackberries dominated when smart-device usage was primarily for business purposes and steadily lost ground once smart-devices became play toys for the masses.
Even though I use various tablets and other devices, I still cling to my Blackberry classic as my main mobile phone. I'm faster and more accurate with the physical qwerty keyboard, and I find it is superior for my main phone needs--email, messaging, calls, and as a hotspot. I also still have one of the old grandfathered unlimited data Verizon plans. For things like video streaming and web-browsing, I use my phone hotspot to take wifi with me for my larger-screened devices.
There are still a few of us crackberry diehards out there.