Epic are a freak of nature, I have never seen an engine move as quickly! Period.. But the point being, in six months time when they have truly covered and surpassed everything Unity and CryEngine has to offer, which is what they're trying to do it's pretty obvious. There is only a finite amount of things you can do with an engine, then they'll be just working on stability and ease of use. All these grand feature sets will slow down, it's inevitable but the question is how far ahead Unreal will be in six months?