Agree with a lot of this, but what a sad situation if the best we can hope for in "control over what it does" is distrust my own device so much that I install firewalls to keep it in check. A much better version of this vision is FOSS.
Most people aren't programmers, people who are programmers don't read the source code of everything they run even if they're allowed to, and even people who try to read the source code for everything they run won't necessarily be able to catch every potential nefarious act. The ingredients list on the back of the box is not the only form of consumer protection in place for food. It shouldn't be the only consumer protection in place for software, either.