He said that the cities will load when you get near the walls, but you won't click on a gate and get hit by a big loading screen, just a small "loading..." popup text in the corner of your screen as the city is loaded in
Direct quote from the interview
so our bigger cities, still have walls, that load you, so that if, if, you know, we were on a next-gen system, that might be something you wouldn’t have to do, memory-wise, you know, to section that off.
here's the quote that came afterwords, the part you were talking about
But at the end, the experience is kind of the same. You would be just walking smoothly into that city, as opposed to clicking the door, waiting for the load, and then going in. I don't know how, amm, I don't really dwell on these things, to be honest, like what we, we can do this, and we can't do this.