Apple is a company, not a government. I haven't traded my liberty for anything. Again, you can buy a different phone – that is where liberty comes into this equation.

If the USG decides to pass a law saying you can only buy iPhones, then we will have more to talk about w.r.t. liberty.

Nothing actually prevents you from modifying your iPhone however you see fit, btw. If you are incapable of breaking Apple's security without bricking the phone, that's a "you" problem.

Completely agree. This is a general issue with technology in general, if someone uses a new technology to their advantage and at your disadvantage, you are essentially forced to adopt said technology just to keep up. In that sense a lot of technological change isn't voluntary. This also explains why a lot of open source/proprietary software is always chasing each other to keep up.