It isn't about being passive; it's about having lives and jobs and other things to do with their time. A heart surgeon may be a genius but he doesn't have time to keep up with the latest research and teach himself PKI, certificates, crypto, and permission models across all the platforms he uses (and keep up to date on those too!)
Users will not waste their time thinkin about trust. The history of our industry is ample evidence that it would be a losing battle. Not to mention a single mistake can be ruinous, requiring absolute perfection 100% of the time (from users and programmers).