I believe physics is still mostly Havok, so it's not them. They are just that... amazing at using it.

The annoying part about the "creation engine" is that it's still just the corpse of the gamebryo engine that they keep reanimating with their own crap on top of it. With its shitty proprietary netimmerse format that basically only exist for them at that point.

With time, people have developed tools to create content for it, but it's yet another area where they went, fuck it, people are going to make our games better, and we don't even need to do anything to make their life easier while they do.