Geez people, they don't have a whole team of people working on UE4. It's one guy doing research and development and maybe playing around with some programming ideas. I rest of Epic, which is probably 60 or 70 people, are working hard on UE3, UT2k7, and GoW.
This tech is at least 5 or 6 years away. We probably won't see it until E3 2009 or something.
Think about it, Carmack does the same. He'll complete an engine and pass it to his team, and while they're working to make Quake3, he'll be researching and starting to code up Doom enigne. Pretty much all game developers that create newer versions of their engines do it this way.
Don't read more into this than there is.