If BTC could be divided only by 10, so that the smallest amount you could own was 0.1BTC, only 210 million people could own it. Don't you think 0.1 BTC is very much more than enough? :-)

In a hyperbitconized world you don't need to worry about it ;)

21,000,000 / 8,000,000,000 = .00262500 BTC BTC Supply / World Population

.1 BTC would put one 40 x greater than if BTC was equally distributed to population.