There are a lot of people outside of the 1st world's lavish lifestyle and deep pockets (filled also with $500 gadgets). If you live in the USA you don't even have to leave your own country to see the other side.
Strike the last sentence and I agree with your comment wholeheartedly.
Interestingly, outside the "1st world" mobile phones are quite common. The speed at which this technology trickled down is amazing, about ten years from yuppies in major cities to subsistence farmers in failed states. Even more amazing is penetration. Most things just don't go that far down the economic ladder at all. Basic, fundamental things like vaccination, artificial fertilizers, electricity or regular phone lines which our grandparents took for granted have been outpaced by mobile phones in many places.
Tablets may be similar enough to mobile phone to hope that the same economics apply and we might see the <$3-a-day majority benefiting by 2020. Hopefully.
Strike the last sentence and I agree with your comment wholeheartedly.