The black market economy is estimated to total $10,000,000,000,000.
If Bitcoin takes over...
.01% of the black market, then 1 BTC = ~ $47
1% of the black market, then 1 BTC = ~$4,761.90
10% of the black market, then 1 BTC = ~$47,619.05
Your math doesn't make sense, but you're not the first that I see making such mistake so I decided to reply.
You're comparing apples and oranges.
When people estimate that black markets are "10T USD large", they're trying to estimate the amount of production outputted by such black markets. A summed value of all goods and services produced, normally in a year time. This has nothing to do with the amount of money that circulates in this market in a given instant, i.e., its "money supply".
For example, an (arguable) estimation of US total economic production is it's GDP of ~14T if I'm not mistaken. That's much more that the entire USD money supply. Granted, you must better define "money supply" as many things may be used as money... but if you take for example the M2 aggregation for USD, that's around
~10 bi according to wikipedia. More than 1000 times lower than the GDP...EDIT: Oups, my mistake, USD M2 is actually close to 10T... so yeah, not that far from the GDP, but that's still just a coincidence.
The M1 is lower. And bitcoin's 21M cap is the M0 of bitcoin. USD M0 is around
2,8T.
Anyway, my point is, money supply != economic production in a year. You can't compare "black market production" with bitcoin's monetary base of 21M and reach any meaningful number.