You're completely missing the safety factor. On European highways passing always occurs on the left, this means nobody should be ever passing you on your right

You're completely missing the safety factor. On European highways passing always occurs on the left, this means nobody should be ever passing you on your right. When you have an emergency like a tire blowout, on a European highway you can safely merge right towards the shoulder with urgency and confidence nobody is coming up fast from behind and overtaking you on that side. In the United States, you cannot make that assumption, people are overtaking on both sides at any time, it's basically chaos.