I use the thing, I know how it works!

Are you saying you'd turn your nose up to a release of Poser that had Unreal Engine in the viewport?
If you did I'm pretty sure you'd be in a less than 1% minority.

I think you have your terminology mixed up, because going through the video tutorials what is being presented is not realtime. Sorry you're aren't going to convince me otherwise when I'm looking directly at it. Those portions of the scenery has to be compiled, then you can work from that, but it's definitely not realtime. That's why the build and play buttons are there. But honestly, as many features are in the Unreal editor itself, it makes more sense to just use the Unreal tools themselves and import your content there. And I'm not sure what you mean by realtime doesn't exist in DS when I can set the iray preview on drop my content and as i move the cursor or change settings it re-renders the scene. I can also do this from the IPR Aux window as well.