The world's wealth in 2007 was more or less 150 trillion $ (USD 1.5 * 10^+12) [1]
The number of people living on earth is more or less 7 billion (7 * 10^+9) [2]
The maximum number of bitcoins is 21 million (2.1 * 10^+7) [3]
This means there is 21*10^7/7*10^9 = 0.03 BTC for every world citizen.
And the current wealth, expressed in the total available number of bitcoins in USD/BTC is 1.5*10^12/2.1*1+7 = 0.5*10^12/0.7*10^7 = 0.7 *10^5 = USD 70,000 / BTC.
With inflation going like it's going now, USD 1 might be (I'm speculating here) worth only 1 UBC (micro Bitcoin) by the time all 21 million Bitcoins are created.
Does this make the bitcoin ultimately usable as a worldwide currency, replacing current currencies?
I think not, and it's built-in.
References:
[1]
http://www.stockmarketfunding.com/getfile/343e5d94-2871-48a5-9aa6-550c3da0bbd2/World-Wealth-vs-World-Derivatives-1998-2007.aspx ,
http://upload.wikimedia.org/wikipedia/commons/thumb/2/24/US_derivatives_and_US_wealth_vs_total_world_wealth_1995-2007.gif/800px-US_derivatives_and_US_wealth_vs_total_world_wealth_1995-2007.gif [2]
http://en.wikipedia.org/wiki/World_population ,
http://www.google.com/chart?cht=lxy&chd=s:ABCDEGHIJLMNOQRSTVWXYabcdfghiklmnpqrsuvwxz01245679,XXXYYZZaabccddeffgghhijjkklmmnoopqqrrsttuuvwwxxyzz&chds=0.0,1.0&chs=160x101&chco=287bf5ff&chls=2.0,1.0,0.0&chxt=x,r,x,r&chxs=0,333333,0,0,tl,333333|1,333333,0,-1,tl,333333|2,000000,11.5,-1,tl,333333|3,000000,11.5,-1,tl,333333&chxtc=0,2|1,2|2,0|3,0&chm=h,cccccc,0,1,1,1|h,cccccc,0,0.5,1,-1&chxp=2,0,82|3,5,50,95&chxl=0:|1960|2009|1:|0|4B|8B|2:|1960|2009|3:|0|4B|8B
[3] Mentioned many times here in this forum
