if you got the privatekey, you can determine all the wallets transactions..
with quantum calculations you could evaluate everybodys privatekey instantly, so it obviously won't be anonymous then..
irrespective of that, btc as we know it today would be dead anyway
Actually, if you can get the private key for an account number, you got the access to that account number, and can steal those coins. Yes, you are correct, we're all in danger then.... of losing our coins.
However, even the person who has control over their account number can NOT tell with whom they have mixed.
So that shouldn't be an issue, correct me if I'm wrong.