It's something of a stretch to say that self-awareness is the state that all humans live within. Many people live their entire lives too distracted by the pretty shiny things to bother questioning their own existence. On top of this, people aren't born self-aware. It's a long process, of living and living, and then one day 'waking up' to the world around you. It's easy to just go on unthinkingly, seeing as you've been doing it since pre-memory.