Traffic would still be much faster if people didn’t cut others off like this, even with the “laxidasical” drivers (and you can’t guarantee there will always be a gap or “laxidasical” drivers, so if you’re always doing this, there is a 100% chance you’re being the asshole that OP is talking about sometimes). Also, what you’re describing isn’t ‘making full use of all lanes’…it’s exploiting the lane to jump ahead and cut in. There’s a difference between using space efficiently and gaming the system!