This is where I disagree with you. The one thing that Facebook should have taught anyone working in the digital economy, it's that once something has mushroomed to getting more than 90% of the market, they damn near undisplaceable (even if they're not a particularly brilliant product - fb never was). I'm worried that by the time this bitcoin killer app comes about, it will face an enormous barrier to entry. Whereas if bitcoin tries to move to the emerging market space first, its natural advantages will make it a damn sure winner.
hmm. I tend to believe/hope Bitcoin's natural advantages will cause it to be adopted. Plus the incredible innovation that can occur around such an open system.
but sure, marketing to emerging markets is good....
I'm pretty sure there have been attempts at bitcoin on feature phones. SMS payments and stuff.
I think most things you suggest will and are happening, but slowly...
So what else is there to do, crowdfund Bitcoin evangelists in emerging markets? Bitcoin tends to create its own evangelists anyway when somebody fully understands it..