Didn't say it should be most expensive. But that I'd expect it to be more expensive than wifi/cellular chips. My expectation may be wrong but that's what it is.
From the iphone5s it was $19 for the A7 but $32 for the wireless section. It may not be as bad anymore. But for quite a few releases the wireless parts seemed unnecessarily expensive.
The estimated price of the high performance chipset and the licensing costs of the IP are different things. Either way it's a small price to pay for international standards that just work. The iPhone would be pretty worthless if it only worked with wireless IP invented by Apple.
Patents affect both the digital and analog parts, but analog hardware is tricky to develop. I don't find it odd at all that the radio parts of a smartphone costs more than the cpu/gpu SoC.
