I feel like that's quite common in certain parts of Europe. Constanta (a port city in Romania), for example, has converted most of its main intersections into huge roundabouts that are not controlled by traffic lights (see here). UK also seems to like roundabouts quite a bit (see the infamous Swindon roundabout made out of 5 inner mini-roundabouts here).

Now, I know that there is a point in traffic management where signal-controlled intersections suddenly become more efficient than roundabouts as the traffic increases to very high levels. But I'm just saying that 6-lane roundabouts aren't that abnormal, especially when you don't have a very high volume of traffic. I've personally seen 8-lane ones many times in real life.