This is highly dubious
What tax authority do you refer to here, specifically? IRS, CRA, or a tax agency of some other country? To tax Satoshi, you would first have to find out what jurisdiction he belongs to, which citizenship he has, who he is and if he is still alive, and whether he is a human being at all. I don't think this is the thing that the tax authorities would want to invest their time and effort in. Anyway, until he sells his coins for fiat, you basically can't tax him in most jurisdictions
You said the answer yourself here,basically no one can tax him in most jurisdictions ,that does not even mean that he wont be taxed ,a million coins in known wallets and just calculate the amount of dollars he is holding in those wallets and you think that the tax authorities wont invest their time for such a huge reward. What tax authority do you refer to here, specifically? IRS, CRA, or a tax agency of some other country? To tax Satoshi, you would first have to find out what jurisdiction he belongs to, which citizenship he has, who he is and if he is still alive, and whether he is a human being at all. I don't think this is the thing that the tax authorities would want to invest their time and effort in. Anyway, until he sells his coins for fiat, you basically can't tax him in most jurisdictions
With the price moving without any hurdle and with the announcement of derivatives market we might touch $10k soon. 
, but in all seriousness, I do not think we are going to reach that price, things are very weird in bitcoin right now, with the pump of bitcoin cash and how slow the bitcoin network is moving. 
