The argument is that, if I invent the Telephone 2.0, I can pretty confidently predict I won't be allowed to capture so much of the profit from it. This provides an incentive for companies to shift their R&D spending towards product development rather than foundational research.
If you invent anything related to cell phone standards and it gets adopted by whatever committee sets the standard, you can become a part of the patent pool, agree to license under FRAND and make money from your research.
