That's nonsense. First off, ARM is able to "keep up" with only tens of millions in profit a year. Second, Qualcomm is one of the richest chip makers. Third, Samsung hasn't been using custom CPUs and GPUS - at all.
It's debatable whether ARM can keep up with custom cores. Both the A15 and A57 designs have been underwhelming from a performance per watt point of view. The A57-based Snapdragon 810 has suffered from thermal issues: http://arstechnica.com/gadgets/2015/04/in-depth-with-the-sna....
Qualcomm is big, but Intel, Apple, and Samsung are all targeting custom cores in this space, and they may reasonably feel like doubling-down on their LTE technology and not trying to compete in that space.
Qualcomm's Krait and Apple's Swift/Cyclone are ARM compatible cores designed in-house from the ground-up. Exynos uses IP cores designed licensed from ARM.
