I just see no 'sweet spot' where some realistic threshold of 'Joe Sixpack' users can use Bitcoin for every day stuff and yet the system remains small enough to be sufficiently decentralized and defensible from subversion.  There is always going to be some point where there is exclusion.

Even back when I first started using the system I was so aware of the cost of doing transactions which remain forever the responsibility of infrastructure operators (including myself) to maintain that I moderated my usage out of consideration.  I find it highly irritating that people demand this level of security for day-to-day purchases.  Similarly, the argument that everyone somehow 'deserves' this level of security is absurd to me.  I don't request nor desire Bitcoin level security for any but the most critical transactions that I do.