Nice, but my figures wouldn't be quite that optimistic, at least in the short term. Most big companies are estimating that by 2020, there will be somewhere between 4 and 5 billion internet users (currently around 3 billion). I'm assuming that not everyone will be using BTC, as there will still be people who don't recognise the advantages and will continue to trust banks. I'm going to go with .1 BTC which is assuming that roughly 5% of internet users are using Bitcoin by 2020.
21 million BTC / 210 million users = .1
If you've got at least a tenth of a BTC, you'll be doing okay.
Although I notice you used the qualifier "eventually", so yeah, I guess if you wait long enough then .0028 might be above average, but that will be in the fairly distant future, I think. Depends how long it takes for people to stop trusting the banks.