It could do that as there may be a higher percentage of the stake in the hands of those who are looking to stabilize the chain for the future. There is still a large amount of Steem coming out into the distribution, it is just being distributed partially to different people, like the 10% to the Steem DAO for development. In time, this might turn into concentration of Stake across the users who are here now, not the ones that are coming unless they want to buy in - which is still and will likely be for a while, very possible.