I've never seen evidence of this, though. It was just something talked about, never seen in footage.
I see no reason to assume that the game once actually contained more content that was cut, vs. comments just being made about things they intended to be in that were never actually implemented in anyway.
Well, they actually showed a fair ammount of content that isn't in the final game. So the question then becomes whether or not that content existed in an actual build of the game or if it was just mocked up entirely for demos.
The more generous assumption is that a lot of what they showed was in the game at one point but couldn't be made to work, didn't scale, or couldn't be completed in time for release.
The more cynical assumption is that none of that stuff ever existed in any sort of working build and all those demos were created using pre-rendered footage and other trickery.
Because things like the portals still exist in the game but have no function I am inclined to believe that there was a develpment build that had things working, at least partially, more in line with what they were describing. That seems more likely to me than the idea that they were pushing features that they knew could never work in the game.