Germany is much more disciplined than the US about being in the right lane and only overtaking on the left. Most of the US has the same rules in theory, but people following the rules less strictly combined with the low speed limits means they don't get the clearly separated speeds for each lane you get on a German Autobahn.
I can understand where you're coming from but driving on a road where everyone has the same speed on average is less stressful than driving on a road with large differences in speed.
The latter requires a good evaluation of the speed of the vehicles behind / in your mirror rather than just checking for whether a vehicle is there. On the former, you can simply match speed with the person in front and you're good to go.
Due to this, ADAS is also broken on roads with high speed differences. It won't alert you of a vehicle is coming 100+ kmh than you in your blind spot.