As a former worker at Blackberry(RIM) cellular chip division (hello fellow RCT-ees), this article explains so much it physically hurts me.
RIM pushed hard to develop its own chip 3G/4G chips because Qualcomm absolutely strangled the company with its licensing cost/terms. They pretty much demanded a separate cellular R&D team (QCT) that duplicates half the effort. All CDMA based phones must contain chips from QCT because Qualcomm holds CDMA patents and they won't license them to anyone. Finally, Qualcomm was, while very technically competent, will give you no assistance whatsoever if you deviate from what they want you to do. Basically 'my way or the highway.'
Edit: As an aside, my heart goes out to Intel's defunct Infineon-based 5G modem team.