Not entirely correct
"BlackBerry once dominated the enterprise, but the unbundling of messaging and data from the hardware, and stiff competition from handset manufacturers and Microsoft meant it was no longer had a compelling proposition."
Was in the enterprise mobe sales world for a carrier when they turned turtle, and this statement kinda glosses over the real issues they had.
True, the quality and desirability of the range had dropped off a cliff in the latter years. No matter how good the Bold 9900 was (and it wasn't, really) - it just felt nasty compared with the stuff Nokia, Apple, and Samsung were churning out by then.
Also true that the whole BB premise of compacting messaging to keep data usage down had become irrelevant as 3G and then 4G became ubiquitous.
Mostly though, it was their supreme arrogance which did them for - I found the collective experience to be hugely dismissive of customers, a certainty that their way of doing things would never be surpassed, and that BES would never have any serious contenders.
Net result; they went stale, just as the likes of Good, MobileIron, BYOD, WP7.5/8, Apple deciding it would (kinda) play in the business space, and the end of subsidised handsets, brought about dramatic change in the market.
The collapse of BB actually had two casualties - Microsoft completely failed with the open goal suddenly presented to them to replace BB as the de facto business phone... eventually killing WP too.