Debian is probably the only example of a successful public public-key infrastructure, but SSH keys are a perfectly serviceable form of public-key infrastructure in everyday life. At least for developers.
Mickens's skepticism about security labels is, however, justified; the problems he identifies are why object-capability models seem more successful in practice.
I do agree that better passwords are a good idea, and, prior to the widespread deployment of malicious microphones, were adequate authentication for many purposes—if you can avoid being phished. My own secure password generator is http://canonical.org/~kragen/sw/netbook-misc-devel/bitwords...., and some of its modes are memorable correct-horse-battery-staple-type passwords. It's arguably slightly blasphemous, so you may be offended if you are an observant Hindu.