Everyone remains IFR, but visual approaches are indeed the way to get a few more flights per hour in the US. Europe decided to instead keep the separation by ra

Everyone remains IFR, but visual approaches are indeed the way to get a few more flights per hour in the US. Europe decided to instead keep the separation by radar, but allows lower radar separation (less distance) compared to the US once aircraft are establish on the localiser (meaning they're on a straight line to landing). The limitation on hourly capacity for both systems is how quickly planes can get off the runway after landing.