Might be an issue with them wanting some time to breath. Otherwise at some point the games areas are always in constant conflict. I would say then that maybe some should happen at the same time, but then maybe consoles couldn't handle all of that going on at once. Technical and design problems are there and not always so obvious, those are the obvious ones to me. Who knows if they are though, or that there aren't others. Of course there's always the simple idea that it's a creative decision. Events are happening, time is passing in universe. Which I don't really mind, though it is sad to see things go.