While I can buy one today for $600 lets suppose that in 5 years the price is $10 000. How difficult will it be for the citizen of a third world country to purchase a coin in order to "opt into" the system?
The smallest unit of BTC is 0.00000001. At this writing, one dollar on the exchanges is selling for about 0.00171 BTC.
If you're suggesting that BTC isn't divisible, I don't believe you're qualified to tell us "what is wrong with Bitcoin."