Once I concede your paranoia, anything is possible.
I refuse to concede they've taken over everything in the world. They simply do not have the power and budget to do that. . . nor the need. They are NOT going to surveil everyone in the world to somehow run across something worthwhile. They are NOT interested in the prattle of innumerable Valley girls or 867V309 or the rest of the ONE BILLION iPhone users when what they want to listen in on is a couple of thousand targeted individuals who are of real interest. It is FAR easier and much less expensive to intercept those targeted individuals' streaming phone calls through the ALREADY compromised carriers!
You are one mentally ill individual if you think that Apple does not have backups to their quality control that checks the QA checkers.
Apple pushes out firmware upgrades from time to time that would overwrite what ever was surreptitiously snuck onto the devices in the supply chain by a mole. . . Remember the larger a conspiracy, the more chances it will fall apart as someone leaks the fact that it is happening. Firmware boot loaders are NOT THAT COMPLEX and the code is easily checked by Apple. Anything added would be noticed by Apple.