I am not concerned of the hackers doing this but, what does concern me is that it is relatively cheap to do at the moment for a corporation/government if it ever got to a point they felt it was worth it. The reason is that once that point comes, it is already too late because it can be done before the rules will change. I would say that anyone buying in very heavily to control a decentalized system is going to be negative for the platform in the long run although, it could turn it into youtube or facebook faster.