If a softfork and hardfork were not adopted by majority of miners, and the thief is able to control a large percentage of the total supply of ETH, how will this affect the ability for ethereum to use POS consensus mechanism?
First, attacker have to withdraw the Ether from the child DAO.
Once it's done the attacker would have to stack ether and apply for being a PoS validator to have an effect on the network. I doubt that anyone would accept it. If it can't become a validator it would just be an ether holder like many other.
So no change for us except our loss of some million of Ether and probably no more giant fund raising and a real lack of confidence in too complex smart contracts.
Note that I wrote "it" when talking about the attacker as we still don't even know if it's a human...
First off they don't control the ETH supply. They grabbed the DAO funds - i.e. they hi-jacked a smart contract NOT the underlying ether.
It doesn't mean anything at all. All the other crypto currencies have hard and soft forked up the wazoo and no one was the wiser.
Same here ... this is a non-event.