It is still considered to be no centre but I think Witnesses still have their powerful decision making. Actually when I think about that I recall how it is in EU when people try to block one country, like President Orban block the help for Ukraine, the same like in US the senate froze the Billion dollar help. So it is always a group of people and not one.I think if everyone leaves they Steem prize definitely will be in free fall and if people go then Witnesses will have no job, because we, users voted for them and brought them there where they are now.