Do you think "satoshi" will ever just randomly log in one day and post something?
No. He's still here, I suspect, but retaining that identity was unnecessarily dangerous.
It seems as if that would be the only way for "satoshi" to ever be proven to be who he is.
Now I very much doubt he intends to do this, but there are certainly other and more reliable ways: signing a message indicating his identity with an address that's provably his (e.g. the genesis block reward address), for one.