While uninteresting to most of us, it boils down to the following.
Physical access to a computer/device = Game over / Compromised
Remote access to a computer/device (even guest privs) = Game over / Compromised
Encrypted communication with a computer/device that requires 3rd party 'trust' = Game over / Compromised
Unencrypted communication with a computer/device = Game over / Compromised
It's a pretty sad state, and there's really not a heck of a lot we can do about it in the short term other than to stop pretending that we have secure devices and communication. People do think about fixing this stuff, but their numbers are nothing compared to those that think about breaking it. I'm pretty sure it's going to get worse before it gets better.