Let's see, I can choose between:
iPhone: Proprietary, unchangeable, walled garden, one vendor, one device.
Android: Open source, changeable, free, many vendors, many devices.
Is this even a choice?
I use a Samsung Galaxy S7. I don't think ANY of your options are reasons for the majority of consumers. They care about price, features and interacting with their friends with another smaller (but highly lucrative target group) caring about fashion and trend. The people that give a shit about the proprietry/open source/walled garden etc stuff is so insignificant that I don't think either side intentionally targets them.
Keep your boss's boss off your boss's back.