When POS will be implemented then we be able to see how much effective this is because whales get benefited from staking as network weight doesn't allow small holders to get reward well. POS is based on the more you hold for longer period the better you will be rewarded. I was looking at market last night when I bought few more wasn't expecting to see under 0.03 ETH anymore but unexpected news hit market. It is buying opportunity anyway not everyone is holding for staking but for doubling or tripling value.
In most cases I have seen in crypto, price of coins often rocket several days before Proof-of-Stakes or masternodes officially activated on main nets. However, after that, weeks or months (usually months) later, price gradually fall down to significant lower price than figure before activation of PoS/ masternodes. Of course, Ethereum is a big altcoin, the second biggest in crypto, just behind Bitcoin, so I hope that Ethereum will be the first exception.