$320 is only the equivelent of

200k people investing $19,200 ever in their life so far (on average)

600k people investing $6,400 ever in their life so far (on average)

2mill people investing $1920 ever in their life so far (on average)

now imagine there being 7 billion people in the world and only 1% of the world ever put 1 months salary (about $1920) EVER into bitcoin
70million people when all coins are mined.. each coin is worth $6400, or currently with 12 mill coins mined. each coin is worth $11,200

so there you go.. theres some possibilities of population uptake and average financial input figures, to get your minds playing about with